LISI GREW UP IN SAN DIEGO, oscillating between riding waves and geeking out. When he was a kid, he says, "my mom could never get me off the beach," but by the time he reached adolescence, in the early eighties, he had forsaken the ocean for an Apple II, programming and designing video games in his bedroom. When his father, a probate attorney, gave him an old VW microbus at age 16, Lisi drifted back to the beach, turning his body to surfing while his mind chased science.

"Math does come easily to me," he says, "but I was always much more interested in what theorems imply about the world than in proving them." While studying physics and mathematics as an undergrad at UCLA, he became obsessed with unraveling the machinery of the universe. Lisi was the top physics student in his graduating class and was accepted to several Ph.D. programs, including UC Berkeley, one of the world's finest. He chose UC San Diego for its funding offer and proximity to the surf, and he lived for eight years with the beach as his backyard.

During the fourth year of his doctorate, Lisi uncovered what he thought might be the kind of deeper pattern he'd been seeking, though it was a bit outside the physics mainstream. It involved a mathematical anomaly that, he speculated, might explain certain properties of an electron. Soon thereafter, his adviser—Roger Dashen, an acclaimed theoretical physicist who had encouraged Lisi's research—died in front of Lisi during a seminar, of a massive heart attack. Devastated, Lisi suddenly found that "no one else was particularly interested in what I was doing." He finished his dissertation on a more conventional topic—hydraulic drag on dolphin skin—and abandoned his discovery as nothing more than a mathematical curiosity.

After earning his doctorate in mid-1999, Lisi glumly realized that postdoc research would require working on string theory, the dominant unifying idea in physics for the past decade. If you got into physics in the nineties looking for a theory of everything, string was the place to be. To skeptics, however, the theory had become a kind of mathematical Rube Goldberg machine, with strange parts and ideas welded on to keep it viable. Its researchers postulated the existence of half a dozen or more additional physical dimensions, folded up inside the ones we know about but well beyond our capacity for measurement. Lisi considers string theory "overly speculative." Even its proponents admit it might be impossible to confirm experimentally.

Like most theoretical physicists, Lisi requires few tools to do his work, which mostly entails reading, doing calculations, and just plain thinking. So, backed by a nest egg of Ph.D. stipend money he'd invested in Apple, he moved to Hawaii with a friend, Brandyn Webb—a computer scientist who shares Lisi's intellectual and independent streaks—to surf and contemplate physics on his own.

"There's an academic establishment that almost values conformity over ingenuity, and he wouldn't conform," says Stephen Applebaum, a doctoral classmate who now works for a medical-device company in San Diego. "He was certainly one of the most gifted people, but he hasn't always been the best at applying himself. Something really has to interest him."

Lisi and Webb became what Webb describes as "freelance perpetual grad students." They mixed serious research (Webb wrote computer-science algorithms while Lisi continued probing the universe) with a taste for adventure, exploring Maui's big waves on surf- and sailboards. Reichart Von Wolfsheild, a Maui-based computer scientist who has been Lisi's friend for nearly a decade, still chuckles when he recalls meeting the pair. Walking on the beach one afternoon, he saw two men with surfboards, deep in conversation. "Even at a distance," he says, "something suggested that these guys don't belong on the beach." As he approached, he noticed that one board was covered in arcane symbols:

For years, Lisi had been having a shaper adorn his surfboards with the mathematical description for the propagation of waves.

"You meet certain people," Von Wolfsheild says, "and you realize instantly that you are going to be friends." He joined Lisi's growing circle of thrill seekers and intellectual enablers and was soon inviting him to house-sit at his home north of Lahaina, where Lisi could access the legendary breaks at Honolua Bay.

"I would never go out there," says Von Wolfsheild. "Garrett's got way more balls than I've got. He's happiest when he's falling down in water."