On this rainy November morning, they're all on hand: Some 64 competitors from 15 countries have gathered in the basement of London's Strand Palace Hotel for the 18th annual World Memory Championship. There's Ben Pridmore, the British favorite, who memorizes a deck of cards in less than 30 seconds. In a photo on the event website, he peers out from behind a Lord of the Rings-style cloak. There's Gunther Karsten, a German chemist who juggles to clear his mind, wears wraparound shades, and in his bio lists the following weaknesses: "restless, demanding, beautiful women" and "luxury cars." There's Taras Bulyga, an 18-year-old Ukrainian who practices 16 hours a day and memorizes by scent. The Chinese competitors wear matching tracksuits and carry mini Chinese flags.

The whole scene resembles a Revenge of the Nerds convention, except for one guy—a dude, really. Ronnie White, the reigning U.S. memory champion, is stocky and solidly built, with blond hair, a square jaw, and dimples. The 36-year-old Texan likes to wear Wranglers and cowboy boots. He eats at Hooters and talks with a twang. When he signed in the night before, a slight, wan British man greeted him with a wry smile. "So, it's Ronnie White," the Brit said, barely disguising a sneer. "You've come to see how the United States measures up against the world, have you?" In the next breath, the guy mentioned Joshua Foer, the 2006 U.S. memory champ and brother of the novelist Jonathan Safran Foer: "He thought he was good, but he wasn't that good."

White was jet-lagged and irritable, but he withheld a retort. He wanted to say, "Hey, the only reason you're speaking English and not German right now is because of us." His Wranglers and his fervent nationalism aren't all that set Ronnie White apart from this crowd. He lacks Foer's Yale pedigree. He's not a genius like Pridmore or an autistic phenom like Stephen Wiltshire, the artist who drew Rome from memory after flying over the city for just a half-hour. White was born to a cop and a driver's-license photographer for the Fort Worth DMV. He's a college dropout turned salesman and Navy reservist. And he's confident that old-fashioned determination and discipline will enable him to open a can of U.S.-grade whup-ass on these brainiacs. Back in 2007 he set his sights on the USA Memory Championship. He placed fourth in 2008. He then devised an innovative and grueling training regimen and returned a year later to win the title. There's no cash prize, but he was rewarded with a plane ticket to London.

So here he is, at 9:30 A.M. on November 12. The competitors sit at rows of tables in a basement conference room, and sheets of paper are placed facedown in front of them. The British announcer takes the mic. "Okay," he says, his face grave, "your minute of mental-preparation time begins now." White, wearing thick military-issue glasses and noise-canceling headphones, leans forward, takes a deep breath, and sinks into the silence. "Neurons at the ready," the announcer cries. "Go!"

Whatever interest Ronnie White had in school waned during college. During his sophomore year at the University of North Texas, he was suspended after earning a 0.9 GPA for two straight semesters. He never finished his degree, but he liked sales, and one day while working as a telemarketer for a chimney-cleaning service, he so impressed a customer with his persistence that he soon found himself selling memory seminars for the man. Eventually White started his own company. He got to thinking that this whole memory thing wasn't that hard. Actually, he began to master it, teaching people to memorize names at networking events and entertaining them with high-energy demos. He often introduces himself to the crowd at a conference, and after asking all 200 people to cover their name tags, he ticks off every single name.

In the wake of 9/11, he enlisted in the Navy Reserve and was deployed to Afghanistan in 2007. It was there that he decided to compete in the USA Memory Championship once he returned to the States. While stationed in Kabul, he'd wrap up a 12-hour shift, go to his bunk, and memorize images and numbers. His superiors were so impressed with his flair for doing security briefings without notes that they had him teach other servicemen how to better memorize the area's geography and tribes. Back home in Texas, after that fourth-place finish, White hired a former Navy SEAL to coach him on "mental toughness." Later that year he sat down in his Dallas apartment to plot his path to victory. He would record his journey in a notebook bound in soft black leather and titled, in gold lettering, THE JIM ROHN LEADERSHIP JOURNAL. White has long been a fan of Rohn, a millionaire motivational speaker. He opened the notebook and flipped past tips for becoming "wealthy, powerful, sophisticated, and influential." "Success," one read, "is neither magical nor mysterious," but rather "the natural consequence of consistently applying basic fundamentals." On a blank page, he wrote: "It is almost 90 days out from the USA Memory Championship, March 7th 2009, in New York. I will have achieved the goal of memorizing a deck of cards in one minute 30 seconds. I will have achieved the goal of memorizing a 167-digit number in five minutes. I will have achieved the goal of being USA Memory Champion."