Kids these days. Just look at them. They’ve got those headphones in their ears and a gadget in every hand. They speak in tongues and text in code. They wear flip-flops everywhere. Does anyone really understand them? Only some people do, or so it seems. They are experts who have earned advanced degrees, dissected data, and published books. If the minds of college students are a maze, these specialists sell maps, so says Eric Hoover in his recent article in The Chronicle called The Millennial Muddle

The article covers the thoughts of leading authors, covering issues they agree on and disagree. It’s lengthy but well worth the read.

Ask them to explain today’s teenagers and twentysomethings. Invite them to your campus to describe this generation’s traits. Just make sure that they don’t all show up at the same time. They would argue, contradict one another, and leave you more baffled than ever.

Figuring out young people has always been a chore, but today it’s also an industry. Colleges and corporations pay experts big bucks to help them understand the fresh-faced hordes that pack the nation’s dorms and office buildings. As in any business, there’s variety as well as competition. One speaker will describe youngsters as the brightest bunch of do-gooders in modern history. Another will call them self-involved knuckleheads. Depending on the prediction, this generation either will save the planet, one soup kitchen at a time, or crash-land on a lonely moon where nobody ever reads.

Everyone in higher education has pondered “the Millennials,” people born between 1982 and 2004 or thereabouts (the years themselves are a subject of debate). Ever since the term went prime time about a decade ago, a zillion words have been written about who Millennials are, how they think, and why they always _______________. In short, Millennials talk is contagious.

Those who have shaped the nation’s understanding of young people are not nearly as famous as their subjects, however. That’s a shame, for these experts are colorful characters in their own right. Some are scholars, and some aren’t. Many can recall watching the Beatles on a black-and-white television, and some grew up just before Barney the purple dinosaur arrived. Most can entertain an audience, though a few prefer to comb through statistics.

In other words, they’re all different. But just for fun, let’s stereotype them as smart, successful, and full of unshakeable opinions. Although they have described one another’s work as “wrong,” “unempirical,” and “wildly mistaken,” these experts have something in common: They are products of their time. In an era when the wants of young consumers have become a fixation for colleges and businesses alike, these unlikely entrepreneurs have fed a world with a bottomless craving for labels.

For as long as human hair has turned gray, elders have looked at their successors and frowned. “Children nowadays are tyrants,” goes an old quotation widely attributed to Socrates. “They contradict their parents, chatter before company, gobble their food, and tyrannize their teachers.” In 1855 a professor at Davidson College described college students as “indulged, petted, and uncontrolled at home … with an undisciplined mind, and an uncultivated heart, yet with exalted ideas of personal dignity, and a scowling contempt for lawful authority.” Albert Einstein opined that while classrooms are many, “the number of young people who genuinely thirst after truth and justice is small.”

Criticizing the young is inevitable, but so, too, is change. In 2000, Neil Howe and William Strauss published Millennials Rising: The Next Great Generation, which cast turn-of-the-century teenagers as rule followers who were engaged, optimistic, and downright pleasant. The authors assigned them seven “core traits”: special, sheltered, confident, team-oriented, conventional, pressured, and achieving. These conclusions were based on a hodgepodge of anecdotes, statistics, and pop-culture references, as well as on surveys of teachers and about 600 high-school seniors in Fairfax County, Va., which in 2007 became the first county in the nation to have a median household income of more than $100,000, about twice the national average.

The authors made a sweeping prediction. “This generation is going to rebel by behaving not worse, but better,” they wrote of Millennials, a term they had coined. “Their life mission will not be to tear down old institutions that don’t work, but to build up new ones that do.” Such thinking promised to give educators, not to mention tens of millions of parents, a warm feeling. Who wouldn’t want to hear that their kids are special?

Mr. Howe and Mr. Strauss were unlikely messengers of this “good-news revolution.” After all, they were not social scientists; they were Washington wonks. At the time, Mr. Howe was an economic-policy consultant and an adviser to the Concord Coalition, a nonpartisan group that supports deficit reduction and Social Security. Mr. Strauss, who had worked in President Ford’s White House and as a staffer in the U.S. Senate, was the director of the Capitol Steps, a satirical singing group. The two shared political views, Ivy League degrees, and a love of history.

The latter had inspired them to write their first book, Generations: The History of America’s Future, 1584 to 2069. Although Millennials Rising would fill the bookshelves of college presidents, deans, and professors, Generations laid the foundation for the authors’ writings on students. Published in 1991, the elaborate chronicle contained a bold, almost mystical theory: that the nation’s entire history had revolved in a predictable cycle of spiritual awakenings and secular crises. In turn, each generation fit one of four distinct archetypes (prophet, nomad, hero, and artist), which have repeated continuously in the same sequence. As surely as autumn follows summer, the Millennials would become the next “hero” generation, destined for coming-of-age triumphs, intent on taking action and building community, just like the “G.I. Generation” decades before.

This retelling of history impressed many reviewers, as well as some influential people. Former Vice President Al Gore—who graduated from Harvard University with Mr. Strauss—called Generations the most stimulating book on American history he’d ever read. He even sent a copy to each member of Congress. Yet Publishers Weekly called the book “as woolly as a newspaper horoscope.” And in academe, scholars chuckled. Nothing like this had ever been written with a straight face.

Arthur E. Levine, a former president of the Teachers College of Columbia University and co-author of When Hope and Fear Collide: A Portrait of Today’s College Student, remains unimpressed. “Generational images are stereotypes,” says Mr. Levine, now president of the Woodrow Wilson Foundation. “There are some differences that stand out, but there are more similarities between students of the past and the present. But if you wrote a book saying that, how interesting would that book be?”

Generations established its creators as pioneers in a burgeoning field. They soon became media darlings, best-selling authors, and busy speakers. Generations would popularize the idea that people in a particular age group share distinct personae and values by virtue of occupying the same “place” in time as they grow up. In turn, this would affirm the notion that Millennials were a riddle waiting to be solved.

These days people all over the world seek Mr. Howe’s advice about Millennials. Mellow and soft-spoken, he listens for rhythms in history. Meandering through a conversation, he can relate the generational significance of the RMS Lusitania to that of F. Scott Fitzgerald, Animal House’s Bluto Blutarsky, and Louisiana’s Bobby Jindal, the first U.S. governor of Indian descent—all in five minutes. Close your eyes, and Mr. Howe, 57, might be a philosophical ex-hippie, riffing on how the universe fits together.

In fact, he’s a well-connected consultant who runs a bustling business, LifeCourse Associates, from the ground floor of his spacious home in Great Falls, Va., just outside Washington. Mr. Strauss died of cancer in 2007, and Mr. Howe now works side by side with three employees, the oldest of whom is 28. Soon the company plans to publish Millennials in the Workplace, which follows several other books, such as Millennials Go to College, Millennials & K-12 Schools, and Millennials and the Pop Culture.

On a recent Monday afternoon, Mr. Howe’s telephone is ringing. Evidence of several half-finished projects covers his desk. Soon he must submit a draft of an article about changing moods throughout American history, which the Harvard Business Review plans to publish. He must prepare for several trips, including a visit to the United Nations, where he will discuss “global aging and demographic security.” On his computer screen are rainbows of charts, on crime, drinking habits, and pregnancy rates among young people.

A deliveryman arrives with packages. “The market is so vast,” Mr. Howe says. “There are so many projects that I don’t have time to do.” As if to prove this, he tells his colleagues that he’s thinking of canceling a contract with a client—a state chapter of the National Guard—that’s haggling over some small details. “They’re all bureaucrats!” he says.

Each year Mr. Howe gives about 60 speeches, often followed by customized workshops. He speaks at colleges, elementary schools, and corporations, and he charges between $5,000 and $14,000, plus travel expenses. He has consulted with various colleges, including Arizona State University, Dartmouth College, Georgetown University, and the University of Texas. His recommendations have influenced the mailings admissions offices send, the extracurricular activities colleges offer, the way professors teach, and even the food students eat. LifeCourse Associates has a partnership with Chartwells, a food-service company that has redefined campus cafeterias and menus at many colleges (think small-group seating and made-to-order meals).

Mr. Howe has also consulted with some of the globe’s biggest companies, including Nike, Hewlett-Packard, and Kraft Nabisco. Recently an investment firm in Prague hired him to do a demographic forecast. Soon the U.S. Army’s lucrative advertising contract will go up for grabs, and Mr. Howe is advising an agency that will compete for it.

A while back, the Ford Motor Company hired him to answer a question: What kind of car would Millennials want to buy? He advised the company to consider the power of “hero myths”—Hercules, Superman, and the boys of Iwo Jima—in its marketing. “Millennials want to do big things,” he wrote in a report for Ford. “Even when driving back and forth to community college in a Focus … their future will be anything but mundane.”

Those are the grand terms in which Mr. Howe thinks, even when he’s just sitting here, shooting the breeze, with his brown walking shoes propped on a desk. When this thirtysomething reporter makes an offhand observation, he remarks, “That’s such an Xer thing to say.” He means Generation X, whose members hail from 1961 to 1981, according to his timeline. Because they tend to be skeptical, hardened pragmatists, he says, they have trouble seeing what’s so great about todays’s kids. For emphasis, he pauses, then says of Millennials, “They are so special.”

And who is Mr. Howe? “A typical boomer,” he says. There is such a thing, he insists. That historical events shape people of a given generation in specific ways is a pillar of his philosophy. The Vietnam War was one event that shaped him. As a student at the University of California at San Diego, he watched a national debate boil. In 1970, when he was a freshman, a fellow student named George Winne Jr. set himself ablaze on the campus while protesting the war and died the next day. Mr. Howe later transferred to Berkeley, where tie-dyed curtains hung in fraternity windows and students bagged classes to hold teach-ins. Everywhere, he saw a cultural rift between young and old. “There was a hysteria in the air,” he says. “A sense that we were headed for the apocalypse.”

A similar feeling swept the nation in September 2001, just as the first Millennials were settling into college campuses. The day after the terrorist attacks on New York and the Pentagon, Mr. Howe appeared on CNN to discuss historical cycles, a subject he and Mr. Strauss had described in a 1997 book called The Fourth Turning, which described four repeating “saecula,” or seasons, of history—awakenings, unravelings, crises, and highs. Did the smoldering twin towers portend a crisis era? The day after the interview, The Fourth Turning appeared in Amazon’s top 20.

Weeks later, Mr. Howe and Mr. Strauss flew to San Antonio to give a keynote speech at the National Association for College Admission Counseling’s annual conference. Attendees stood and sang “God Bless America.” In the convention center, as on college campuses and town squares, people perceived that a line had just been drawn in the sand of history. Soon Newsweek published a cover story called “Generation 9-11,” which described the unprecedented attacks as a “defining moment” for high-school and college students.

The aftermath made many people more receptive to the message of Millennials Rising, Mr. Howe believes. “Whenever there’s a change in social mood,” he says, “it makes thinking about generations clearer.”

As cheery as a bouquet of roses, the good news about Millennials intrigued many people who recruit, serve, and teach college students. Administrators and professors had long stereotyped the students walking through the campus gates, but as the 21st century began, higher education was evolving in ways that made the time ripe for a new and tidy explanation of contemporary undergraduates.

For one, colleges turned to marketing as never before. Among selective colleges, the decade brought intense competition for applicants. Even among less-selective institutions, recruitment meant expanding into new territories and reaching out to more-diverse students. Early-acceptance programs ballooned. Parents morphed into co-purchasers. Deans embraced holistic evaluations, attempting to peer deeper into hearts and noggins. Sophisticated statistical models predicted who would enroll—and at what price.

Meanwhile, technology changed the application process. The Web was the Wild West of the enrollment profession, and with it came “stealth applicants” and much uncertainty. Many admissions officials found themselves under pressure to meet ambitious enrollment goals while protecting the bottom line. Understanding the whys of students’ attitudes and behaviors was more crucial than ever.

Amid this complexity, the Millennials message was not only comforting but empowering. “It tickled our ears,” says Palmer H. Muntz, director of admissions and an enrollment-management consultant at Lincoln Christian University, in Illinois. “It packaged today’s youth in a way that we really wanted to see them. It gave us a formula for understanding them.”

Over time, however, Mr. Muntz started to doubt the formula. Each year he visited many rural and urban high schools. He did not meet many students who had sweated their grades or taken standardized tests multiple times. Millennials Go to College, published in 2003, described an “intense new emphasis on preparation and planning” among students who were competing in a college-application “arms race,” who thought about their futures in “five- or 10-year time horizons,” and who perceived the high achievements of their peers as “a constant source of personal pressure.”

Yet Mr. Muntz met few students who seemed to have these “pressured” and “achieving” traits. Generally, he saw what he had always seen—sharp kids, average kids, and kids with weaknesses, all with hopes and worries, floating day to day through teenage life. He wondered if the sample of students in Millennials Rising had corrupted the findings. After all, most students do not apply to top-20 colleges.

And so Mr. Muntz confronted a fact: To accept generational thinking, one must find a way to swallow two large assumptions. That tens of millions of people, born over about 20 years, are fundamentally different from people of other age groups—and that those tens of millions of people are similar to each other in meaningful ways. This idea is the underpinning of Mr. Howe’s conclusion that each generation turns a historical corner, breaking sharply with the previous generation’s traits and values.

Several researchers have blasted this theory of “nonlinear” social change. Some cite data from the Cooperative Institutional Research Program at the University of California at Los Angeles, which has conducted an annual survey of college freshmen since 1966. The survey, which provides a longitudinal view of trends, suggests that many changes among students happen gradually, not abruptly.

Moreover, the survey complicates the Millennials theory in numerous ways. According a recent report by the program, “American Freshmen: Forty Year Trends,” today’s students are not significantly busier, more confident, or more positive than they were in recent decades. Though more say they want to contribute to society, more also cite “being well off financially” as a goal. They are only slightly less likely to say they want to go to college to get a job, make money, or go to graduate school. They are not any more or less cooperative or competitive, nor do they seem more interested in developing a meaningful philosophy of life

Not long ago, Mr. Muntz attended a presentation about those findings. He has since decided to stop thinking in generational terms. “You can’t just take one stamp and put it on this generation,” says Mr. Muntz. “But it sure was nice when I thought I could.”

In other corners of academe, many people have wrestled with similar thoughts. Among those who serve students, Millennials theories seemed to offer crucial clues during a time when the profession was changing rapidly. Over the last decade, the umbrella of student affairs widened to cover a vast array of programs and services. More and more staff members became co-educators and crisis managers. “Student engagement” turned into a full-time mission amid growing concerns about retention. Mental-health services multiplied. Colleges built walls for students to climb and heated pools for them to swim. They opened parent offices, started parent orientations, and published parent newsletters.

Studying students went hand in hand with the growing interest in measurements of “learning outcomes” outside the classroom. “We really had to know what our students were thinking, feeling, and learning in everything we were doing,” says Richard H. Mullendore, a former vice president for student affairs at the University of Georgia. He credits Mr. Howe and Mr. Strauss for several keen observations about Millennials, especially their tendency to enjoy close relationships with their parents. But he reached a conclusion similar to Mr. Muntz’s. He need look no farther than the town of Athens, one of the poorest in the state, where high schools have much lower graduation rates than most of those that send students to Georgia. “A large number of young people have been totally overlooked in this literature,” Mr. Mullendore says. “Their battles have not been similar to anything those other students have faced.”

Some student-affairs professionals struggled to square Millennials Rising with what they saw on their campuses each day. A decade ago, Gwendolyn Jordan Dungy, executive director of Naspa-Student Affairs Administrators in Higher Education, recognized the inherent appeal of the Millennials framework. “People in student affairs have this philosophy of believing in the basic goodness of young people,” she says. Yet she believes that the book is longer on generalizations than on truth. After all, a competing narrative about students had developed. In it, more of them were anxious and depressed, and more were as self-centered and demanding as diners in a crowded restaurant. “We heard that this was the next great generation,” Ms. Dungy says, “but many people just weren’t seeing them that way.”

Jeannine C. Lalonde was skeptical from the start. She read Millennials Rising when she was an assistant hall director at Boston College. “To be frank, I just laughed,” says Ms. Lalonde, now senior assistant dean of admissions at the University of Virginia. “It was really singular in its approach.” As a residence-life staffer, she believed her job was not only to support students, but also to challenge them. Yet some students, who seemed to see themselves as customers, did not want those challenges—they wanted problems solved for them. “I was seeing many of these positive things, but I was also confused by all the entitlement I was seeing,” Ms. Lalonde says. “Where was that in the book?”

Jean M. Twenge asked the same question when she read Millennials Rising. After all, she had spent years in library stacks, studying generational differences. While working toward a Ph.D. in personality psychology at the University of Michigan at Ann Arbor, she discovered questionnaires that academic psychologists had designed to measure personality traits and attitudes. The questionnaires had been used widely since the 1950s, and most had been completed by college students and schoolchildren. That allowed her to compare changes in young people over time.

Like Mr. Howe and Mr. Strauss, Ms. Twenge concluded that when people were born shapes them more than (or at least as much as) where they were born or who their parents were. Yet she did not buy the idea that changes in students came suddenly. “Changes are linear; they happen over time,” she says.

In Millennials Rising, Ms. Twenge did not find sufficient evidence to compare this generation with previous ones. Moreover, her findings did not come with a big smiley face. In 2006, Ms. Twenge described her research in her first book, Generation Me: Why Today’s Young Americans Are More Confident, Assertive, Entitled—and More Miserable Than Ever Before. “I see no evidence that today’s young people feel much attachment to duty or to group cohesion.” Ms. Twenge wrote. “Young people have been consistently taught to put their own needs first and to focus on feeling good about themselves.”

Ms. Twenge defined Generation Me as anyone born in the 1970s through the 1990s. Born in 1971, the author thus included herself in this generation. Many children of this era, she wrote, had been raised in a culture of constant praise, in which everyone got trophies and parents filled their children’s ears with assurances that they were unique, talented, and special. Call it too much of a good thing. Among other outcomes, she found, the “self-esteem movement” had led to a rise in narcissism. She had analyzed some 15,000 students’ responses to a questionnaire called the Narcissistic Personality Inventory between 1987 and 2006. The inventory contained statements like, “I think I am a special person,” “I can live my life any way I want to,” and “If I ruled the world, it would be a better place.” Over time, the percentage who scored high had risen substantially.

Mr. Howe and Mr. Strauss had labeled Millennials as “special,” which they described as a positive trait, a feeling of self-worth instilled by doting parents. Generation Me cast this same feeling in a darker light.

Ms. Twenge even suggested that the rise in volunteering Mr. Howe and Mr. Strauss had described might not indicate an increase in altruism. After all, students knew that doing community service helped them fulfill requirements for the National Honor Society and perhaps get into college. Over time, Ms. Twenge’s research created a buzz in higher education, even prompting mention on Late Night With Conan O’Brien. Before long, Mr. Howe and Mr. Strauss pounced on her findings, questioning her research and her motivations. In an opinion piece published in The Christian Science Monitor, they wrote, “No message … could be so perverse and contrary to fact as the accusation of selfishness.”

Mr. Howe has described Ms. Twenge as having a “Manichaean” view of the world. He has accused her of mistaking self-confidence for narcissism. “You can tell young people that they’re not special and see if that works,” he says. Colleges and companies alike, he believes, can “leverage” this feeling of specialness among young people and turn it into good things.

Ms. Twenge has stopped short of calling students selfish, but her message has prompted many questions. For one, who is this woman who upset the Millennials’ apple cart?

As it turns out, Ms. Twenge is an engaging teacher who draws bell curves on napkins and has no time for nonsense. An associate professor of psychology at San Diego State University, she insists that she likes her students, at least most of them. The ones who ask if they can take final exams early so they can go to Las Vegas, or who grub for grades and demand extra credit? Not so much.

Ms. Twenge’s research has given her insights into her personal life. About 10 years ago, she went over the narcissism inventory with a man she was dating. He scored in the 99th percentile, which, she says, confirmed problems in their relationship. After their breakup, she vowed not to end up with the same kind of person. So on her fourth date with another man, she asked him to complete the same questionnaire. He scored low, and they eventually married. She calls the inventory “the boyfriend test” and has given copies to students who want to find out if they’re dating a narcissist.

On a Tuesday in August, Ms. Twenge is teaching a course on personality. She arrives a few minutes late because she had to do a radio interview about public perceptions of generations. Today’s the last class before the final exam, and students have many questions. One asks if she can get extra points because she listened to Ms. Twenge’s interview on the way to class. The answer is no.

While reviewing the semester’s lessons, Ms. Twenge walks over to tug on a student’s sleeve to demonstrate what a clingy, anxious person might be like in relationship. Later she introduces some of her research on narcissism. She shows a slide of Whitney Houston from way back and asks if any students remember the singer’s 1986 hit “Greatest Love of All.” The sight of Ms. Houston’s hairdo draws laughter, but Ms. Twenge is serious about one of the song’s lyrics—”learning to love yourself is the greatest love of all.” In the 1950s, she explains, this very idea would have been beyond weird, but these days, it’s normal—and unhealthy. She draws a distinction between self-confidence and narcissism, the latter being associated with a lack of empathy and with aggression after insults.

Ms. Twenge then shows her students a list of statements, such as “Be yourself,” “You are special,” and “You can be anything you want to be.” Then she asks a question: “These phrases are individualistic, but are they good advice?”

“No!” several students say.

“Good,” Ms. Twenge replies with a grin. “I’ve taught you well.”

“Are you just being defensively pessimistic?” one student asks.

“Maybe,” Ms. Twenge replies.

“Defensive pessimism” is a psychological strategy in which one considers worst-case scenarios and braces for the worst, to avoid disappointment. It’s fair description of her, not to mention of her book, says Ms. Twenge, who describes Generation Me as a warning about young people, not an indictment of them. “These kids didn’t raise themselves,” she says. Ms. Twenge tries to practice what she preaches. She does not ask her young daughter, Kate, too many open-ended questions, like “What would you like for dinner?” She does not tell her that she’s special, nor does she buy her clothes that say things like “Little Princess.”

Ms. Twenge does, however, take her along on speaking trips. This year she has given about 15 presentations, for which she charges between $1,000 and $5,000. Recently she has spoken at PepsiCo, McGraw-Hill, and the Florida Association of Blood Banks, where she encouraged attendees to appeal to young peoples’ sense that they can make a personal difference by donating their blood—”Make it about them.” During her presentations, she asks her audience to sing along to a song that’s become popular in preschools. It’s a song she dislikes. Sung to the tune of “Frère Jacques,” it goes, “I am special, I am special, look at me, look at me. …”

Teenagers who grow up with this chorus in their heads have a venue for self-absorption that their parents never imagined. It’s called the Internet. Ms. Twenge argues that Facebook and other social media have fed a bonfire of vanity among young people. On the other side of the country, a scholar named Mark Bauerlein has reached a similar conclusion.

Mr. Bauerlein, an English professor at Emory University, in Atlanta, is the author of The Dumbest Generation: How the Digital Age Stupefies Young Americans and Jeopardizes Our Future. The sub-subtitle turns an old generational rallying cry on its head: “Don’t trust anyone under 30.”

Mr. Bauerlein (who writes for The Chronicle Review’s Brainstorm blog) concerns himself with only one generational trait, what he calls the “intellectual condition.” Today’s students, though blessed with limitless high-tech wonders, have squandered these tools, using computers mostly for their amusement—chatting, networking, and posting online updates about themselves, Mr. Bauerlein argues. Teenagers, he writes, “are drowning in their own ignorance and aliteracy.” To tout the technological skills of today’s students, he continues, “feeds the generational consciousness that keeps kids from growing up.”

Mr. Bauerlein, 50, directed the survey reported in “Reading at Risk: A Survey of Literary Reading in America,” published by the National Endowment for the Arts in 2004. It found a sharp decline in reading among all age groups between 1982 and 2002, and the largest drop was among people between 18 and 24. In The Dumbest Generation, he cited numerous other studies that affirmed that today’s students were reading less and absorbing fewer facts than their predecessors had. His own experiences in the classroom also informed his conclusions. He describes most of his students as highly professional; he encounters fewer and fewer who seem interested in culture, in wrestling with ideas. “Many of them have a mercenary attitude about the university, and they regard humanities as an interruption,” he says. In this, he foresees cultural doom.

Not long ago, Mr. Bauerlein faced off against Mr. Howe in Washington during a debate sponsored by the American Enterprise Institute. He thinks Mr. Howe has many good insights, but he sees limits to them. “There’s an investment in being enthusiastic—maybe too strong an investment in that,” Mr. Bauerlein says.

Like Ms. Twenge, Mr. Bauerlein describes his book as a labor of love, not scorn. “It’s a provocation with a generous aim,” he says. “In the raising and rearing of young people, a critical voice is essential. They have to hear someone knock them down, and if they fight back, that’s good. It’s part of the health of a culture from generation to generation.” Several technophiles in academe have cast Mr. Bauerlein as a Luddite who clings to a single (and dated) definition of literacy. He invites them to his classes. “They’ve never sat across from a freshman who comes in and says, ‘I don’t want to read any novel.’ It’s a lot easier to be sanguine about students if you’ve never encountered that.”

The professor acknowledges that the book’s title is incendiary. As his agent assured him, bold proclamations help get authors on the radar, though his conclusions are more nuanced than the cover might suggest. Still, when he told his wife that planned to dedicate the book to her, she said no thanks. She knew that a book that called roughly 100 million people dumb would make him a public enemy. Sure enough, since the book came out last year, Mr. Bauerlein has received scores of angry e-mail messages, many of them from teenagers. Recently, a 13-year-old wrote that he was “great, big hypocrite.” Another began: “Dear sir, you are an ass.”

A curious thing has happened, though. Mr. Bauerlein, who says that he has responded to each message he has received, has become engaged in several positive, continuing dialogues with some of the parents and students who wrote to him. It’s a testament to the possibilities of the very technology he has questioned.

As the Millennial decade rolled on, Mr. Bauerlein and other professors encountered waves of teenagers who had grown up using search engines and instant messaging, and they wondered how those experiences might affect the way students learned. Many students were indeed behaving more like fussy consumers. It was not clear how far their demands would go for personalization, satisfaction, and instant gratification. This uncertainty led to a larger question about supposed generational traits. Were educators to see them as something to indulge—or to cure?

Many instructors who weighed this question with regard to technology have tried to meet students where they are, by incorporating Facebook, Twitter, and all kinds of multimedia platforms into their teaching. Siva Vaidhyanathan has no problem with such innovation per se, but he questions the notion that regardless of what they are teaching, instructors must do all they can to please Millennials by embracing technological portals like some kind of magical device. “There’s this expectation that your No. 1 job is to pander to this exotic alien consumer,” says Mr. Vaidhyanathan, an associate professor of media studies at the University of Virginia. “At that point, you cease being a teacher and you are simply selling yourself to an audience that might not be interested in buying.”

Mr. Vaidhyanathan has read Millennials Rising. He says Mr. Howe and Mr. Strauss might as well have written a book on how to reach out to Geminis. “If you work in higher education, the first thing you should do is throw out all their books,” says Mr. Vaidhyanathan. “Generational thinking is just a benign form of bigotry, in which you flatten out diversity. This is debilitating to the job of trying to work with young people.”

Over the last decade, commentators have tended to slap the Millennial label on white, affluent teenagers who accomplish great things as they grow up in the suburbs, who confront anxiety when applying to super-selective colleges, and who multitask with ease as their helicopter parents hover reassuringly above them. The label tends not to appear in renderings of teenagers who happen to be minorities, or poor, or who have never won a spelling bee. Nor does the term often refer to students from big cities and small towns that are nothing like Fairfax County, Va. Or who lack technological know-how. Or who struggle to complete high school. Or who never even consider college. Or who commit crimes. Or who suffer from too little parental support. Or who drop out of college. Aren’t they Millennials, too?

Many pieces of the Millennial puzzle are missing, says Fred A. Bonner II. He’s one of several researchers who have examined the experiences of nonwhite students in hopes of broadening the understanding of the generation.

Mr. Bonner, an associate professor in the department of educational administration and human resources at Texas A&M University, has described how the prevailing generational descriptions focus narrowly on the experiences of majority populations. He believes the Howe/Strauss model is useful, but limited. “Many other kinds of students have not come from backgrounds where they felt safe, sheltered, and secure, or from schools that recognized their gifts and talents,” says Mr. Bonner, who is 40.

During class discussions, he has listened to black and Hispanic students describe how some or all of the so-called seven core traits did not apply to them. They often say the “special” trait, in particular, is unrecognizable. “It’s not that many diverse parents don’t want to treat their kids as special,” he says, “but they often don’t have the social and cultural capital, the time and resources, to do that.”

Mr. Bonner is a co-editor of a forthcoming book, tentatively titled Diverse Millennials in College, which Stylus Publishing plans to publish in 2010. In recent years, Mr. Bonner has also done some generational consulting of his own. So far that work has been limited to speaking engagements at two- and four-year colleges. Generally his audiences understand that the experiences of a black Millennial from, say, Houston may differ greatly from the experiences of a white student from the Houston suburbs. After all, people who work in higher education see plenty of reminders that the when of student’s birth is but one factor in that student’s development. Where a student is born, who a student’s parents are, and how much money they have—all these things influence that student’s educational opportunities, scores on standardized tests, and expectations of college.

“Some folks are using this as a template and a cookbook,” Mr. Bonner says of Millennials descriptions. “It makes it very difficult to see and understand variations because people who don’t fit the recipe may be viewed as outliers. That anesthetizes nuances.”

At the same time, generalizations are often as necessary as lifeboats; they allow people to navigate a sea of complexity. This is the very reason that many people in higher education have found Mr. Howe so useful.

The list of those who swear by his work is long. One is Lisa A. Rossbacher, president of Southern Polytechnic State University, in Georgia. After hearing Mr. Howe at a conference a year ago, she invited him to come talk to faculty and staff members on her campus recently. The university has made many changes that incorporate his insights into Millennials. To acknowledge their comfort with technology, it offers more hybrid courses that combine classroom and online learning. To satisfy their wish for more feedback, it encourages instructors to assign more group work and more short, graded assignments. To involve their parents, it provides them with cellphone numbers for the vice presidents for students affairs and for enrollment.

Those are all changes that the university probably would have made anyway, Ms. Rossbacher suspects, only without knowing exactly why. “We can see the trends, but Neil gives us the context to help us understand why we’re seeing the things we are seeing,” she says. “He speaks as an outside authority, as a prophet not in his own land.”

Among other things, Mr. Howe is a gifted storyteller. He describes generational membership as an underappreciated part of people’s stories, but concedes that it’s just one part. So perhaps his conclusions about the generations are best thought of as medieval maps, with their rough approximations of a land’s boundaries and rivers. They suggest a general features, though they do not give you all the specifics you would need to get somewhere. Like inside a particular student’s head.

These days Mr. Howe’s talking about the next birth cohort, born 2005-25, which he calls the “Homeland Generation.” According to his framework, those Americans will fit an “artist” archetype. “Such generations tend to be remembered for their quiet years of rising adulthood,” he has written, “and their midlife years of flexible, consensus-building leadership.” One day Mr. Howe hopes to start a nonprofit group devoted to the study of generational differences. After all, historians may never fully embrace it.

“Academia gives this no home despite the fact that managers of for-profits and nonprofits find it so valuable,” Mr. Howe says. “Why is it that I constantly get calls? This is a demand-driven business.”

It’s a business that begets business. In the Millennials industry, plenty of people owe their success—not to mention their talking points—to Mr. Howe. If you’re a career counselor on a college campus, odds are good that many of your students go on to work for companies that have paid experts to come and explain how to make young workers happy and retain them. Perhaps the expert was Mary Crane, who was once a lobbyist, then an assistant chef at the White House, before becoming a full-time generational consultant for Fortune 500 companies and law firms. Recently she was featured on a 60 Minutes segment about Millennials. Or perhaps it was Eric Greenberg, a philanthropist who found the time to write a book called Generation We: How Millennial Youth Are Taking Over America and Changing Our World Forever in between running Beautifull Inc., a health-food company, and endowing genetics laboratories.

Lynne Lancaster, a management consultant and “cultural translator,” is a co-founder and partner of BridgeWorks LLC, which offers companies advice on bridging generational divides among employees. So does Kanna Hudson, 26, a former academic counselor who works for a consulting company called Another consultant, Scott Degraffenreid, a former forensic accountant, wrote Understanding the Millennial Mind: A Menace or Amazing? and patented the term “crash-test geniuses” to refer to young people’s willingness to “reboot” and learn from failures, even if it means walking away from their jobs. Eric Chester, a former teacher, runs a consulting business called Generation Why; his Web site describes young people as “weird-looking and impossible to understand.”

Such descriptions are reminders that most renderings of Millennials are done by older people, looking through the windows of their own experiences. So in any discussion of generations, it’s only fair to give a Millennial the last word. This is tricky exercise, however. After all, it’s easy to find one who agrees—or disagrees—with the idea that students are team-oriented, or narcissistic, or anything. And many have given generational labels no more consideration than the ingredients of their breakfast cereal.

Susanna Wolff, however, has thought a lot about the differences between younger and older people, at least in terms of their mastery of technology, a theme she mines for laughs. Ms. Wolff, a senior at Columbia University, compiles a weekly feature called “Parents Just Don’t Understand,” for, a popular Web site. Submissions come from all over the country, about mothers who don’t understand how e-mail works and fathers who ask about joining “MyFace.”

Besides technology, however, Ms. Wolff believes that people her age have few common experiences to bind them together the way Millennial theories describe. When she hears the term “Millennial,” she thinks of marketing executives huddled around tables, looking at pie charts and figuring out how to sell stuff. “When every commercial is marketed to you,” she says, “it feeds the idea that everything revolves around you.”

Ms. Wolff sees many things that complicate generational generalizations. Take her own family. Although she’s close to her parents, they call her more than she calls them. In fact, she talks most often to her grandmother—who recently sought her advice on starting a blog.

Although she is wary of the many predictions about her generation, Ms. Wolff, 21, offers a guess about what people her age will be like in, say, 20 years. “We’ll be really good at the technology we’re familiar with and really bad about learning anything new,” she says. “And we’ll complain about the young people.”

TomorrowToday Global