If anyone can make string theory accessible, Greene can. All of his colleagues agree he's a whiz at explaining things, the kind of person who can make counterintuitive concepts -- like the warping of time, for example, or the curving of space -- seem as normal and natural as rain. Thanks to Stephen Hawking, the public's appetite for books about particle physics and cosmology has also swollen considerably in recent years; A Brief History of Time stayed on the best-seller list for months, even though almost no one understood a word of it.

Greene has an advantage over Hawking. The Elegant Universe is actually comprehensible. In many places, it's even compulsively readable. Greene is funny and handy with metaphors, using such diverse examples as peach pits, insider trading, and ants on a garden hose to illuminate his basic points. Small wonder that he had at least three New York publishing houses vying for the rights to the book.

Of course, string theory won't really have arrived -- the way chaos theory did a few years ago -- until Michael Crichton puts it in a novel and Jeff Goldblum starts nattering about it in Jurassic Park III. But here again, Greene may prove useful, because an appealing messenger will surely hasten the dissemination of the string gospel. In a field full of men who tend to look as if they were drawn by naughty, drunken cartoonists (the thick glasses, the wild hair, the asexual posture), Greene is a striking standout, and it's not just because he's attractive and wears contacts. In high school, Greene won math competitions and judo tournaments. At Harvard, he performed in musicals. At Oxford, he hung out with George Stephanopoulos.

"Physicists tend to be introverted," says Frank Wilczek, a leading particle physicist at Princeton's Institute for Advanced Study. "Brian's definitely at the extroverted end of the spectrum. And the charismatic end." He giggles. (Wilczek giggles a lot. When he first hatched the concept of the axion particle, he named it after a laundry detergent. Just for a giggle.) "Physics requires the kind of personality that's ready to sit down for a long time and learn difficult things and do abstract calculations," he continues. "That's almost the polar opposite of interacting with people -- and having fun." His peers, he notes, aren't particularly glamorous. "Physics is far removed from primal urges. It has nothing to do with sex, power, or getting fed."

Greene probably got some of his expansiveness from his father, Alan Greene, a composer, vocal coach, and former vaudevillian. He and Brian's mother, Rita, encouraged their children to express themselves, and it seems to have worked. "I consider lecturing a form of performance," Brian often says, and clearly, those acting lessons have paid off.

"He has this great reputation," says Greg Langmead, a 25-year-old graduate student in the Columbia math department. "Even among students who haven't taken anything with him. He's a great communicator, he's charismatic, he's clearly top-of-the-heap intellectually. So the fact that he has gobs of raw physical appeal on top of that -- it gives him a really serious mystique."

Yet what's good for booksellers, readers, and students may not be good for Greene's own career as a scientist. When he first started writing The Elegant Universe, Greene didn't even tell most of his colleagues. "Brian wasn't sure the community would place the same value on this kind of communication as he did," says David Morrison, a Duke University mathematician with whom Greene did groundbreaking research. "I think he was concerned that people would think he'd left the playing field."