So how many aimless and unmotivated young men do you know? If physician and research psychologist Leonard Sax is correct, doubtless you know many of them—or are one yourself. Do you spend most of your time playing video games? Are you taking medication for ADHD? Are you indifferent to school or a career? Then this book is about you.

Young women, on the other hand, seem to be surging. Elite colleges have a glut of accomplished female applicants, but have to work to find enough qualified men to achieve something close to a 50-50 male-female admissions ratio. By age 35, 35 percent of American women have earned a college degree, while only 23 percent of men have done so. Some experts say that within 10 years, twice as many women as men will have finished college.

And when these men and women form relationships or marry, all too often the woman is out conquering the world while her husband simply continues what he was doing before they got together—which is to say, not much. Even stay-at-home dads are in too many cases merely sitting around eating ice cream and watching TV with the kids, leaving the heavy housework to the mom when she finally gets home from work.

This territory has been covered before, but Boys Adrift: The Five Factors Driving the Growing Epidemic of Unmotivated Boys and Underachieving Young Men presents a straightforward argument that incorporates solid research and, thankfully, does not blame feminism. What he does blame is a combination of social and scientific factors that have taken place over the last 30 years. These include the way students are taught in school, prescription drugs, video games, the ubiquity of environmental estrogens caused by pollution, and the devaluing of positive masculine roles on TV, in the movies, and in real life.

Today, Sax writes, schools have "abolished" competitive formats and emphasize simulated over physical experience. "Nature," he writes, "has been replaced by computer screens and fancy indoor toys." Schools have also accelerated the early elementary curriculum, which works against the way most boys' brains develop. For instance, Sax writes, because boys mature more slowly than girls verbally, "trying to teach 5-year-old boys to learn to read and write may be just as inappropriate as it would be to try to teach 3-year-old girls to read and write." All of this turns boys off to school at a young age and causes behavior problems.

Many of these behavior problems end up being labeled ADHD and medicated with Ritalin. In 2007, boys are 30 times as likely to be taking medication than in 1987. Sax is no fan of the drug. "What parents don't know," he writes, "is that even relatively short-term use of these drugs, for just a year or perhaps less, can lead to changes in personality. The boy who used to be agreeable, outgoing, and adventurous becomes lazy and irritable."

Video games fry your brain, too. "Playing video games," Sax writes, "gives boys the reward associated with achieving a great objective, but without any connection to the real world." The games "have the power to displace and distort the motivation of boys and young men, so that they no longer have the same interest in real-world success and real-world achievement."

And what about those endocrine disrupters—the ones that change whole rivers of male fish into females? Hormone-disrupting chemicals are found in everyone's bodies these days, a product of the ubiquity of plastic. Girls are now starting puberty at age 8, but boys' development seems to be slowed. As a result, "middle school has become a very strange place," with the girls appearing to be about 16, but the boys about 10.

Finally, where are the positive, mature male role models? Boys, Sax argues, must be taught to be men—and right now, most boys aren't seeing anyone much better than Homer Simpson or 50 Cent to live up to, in real life or on TV. "What does it mean to be a man today," he writes, "a mature adult man?"

Sax recommends pulling the plug on the games, making Ritalin a rare prescription, changing teaching methods in the early grades, and getting all these boys outside already, to play real games on real dirt.

He does manage to get his message across without being too nostalgic for an idyllic past that never actually happened. (After all, worries about the damaged masculinity of American boys go at least as far back as Teddy Roosevelt's laments about what the end of readily available Indian killing and buffalo slaughtering would do to the character of the nation's white male youth at the end of the 19th century.) Sax also makes sure to remind us that he doesn't think girls have it easier. But at a time when it is almost unusual to find a young man with drive and direction, Sax's work is an important part of a growing public discussion.