To fully appreciate how much Lance Armstrong owes to Johan Bruyneel, maybe you'd have to watch Bruyneel steer a speeding car with his knees as he chases Armstrong through curvy mountain roads while juggling two-way radios, a cell phone and a map, and calls out tactical orders to the cyclist. Or maybe you would have to go back to those days just out of the hospital bed, when Armstrong couldn't imagine winning a bike race, and was just content to win his life back, until Bruyneel suggested he might be capable of more. Who, exactly, is Johan Bruyneel? "Johan Bruyneel is the first person who put Lance Armstrong and the Tour de France in the same sentence," Armstrong says.

It was 1999, and Armstrong was a mentally fragile and physically depleted athlete who wasn't sure he had a future in cycling after almost dying of cancer. None of the major teams would give him a job, so Armstrong accepted an offer from the U.S. Postal team. Bruyneel was Postal's new directeur sportif, cycling's equivalent of a head coach.

In their first meeting, Bruyneel said to him, "I think we should talk about the Tour de France."

"Okay," Armstrong said. "Maybe I could win some stages."

"No," Bruyneel said, "I mean the whole thing."

Since then, Armstrong and Bruyneel have become professionally inseparable, as Armstrong has won five consecutive Tour de France titles. Should Armstrong win a record-breaking sixth title, as he is seeking to do over the next 10 days and thousand miles through the dire ascensions and swooping descents of the Pyrenees and Alps, Armstrong will be called the greatest cyclist in history. But Armstrong would be the first to tell you cycling is a team sport, and that while he's the one who rides the blacktop and climbs the jagged icy peaks, without Bruyneel, he might never have won a single Tour much less have a shot at a record. Though Bruyneel is unrecognized outside of his own sport, he has been to Armstrong what Phil Jackson was to Michael Jordan, an arch-strategist and a critical influence, who has taught one of the all-time greats how to get the absolute most out of himself, and without whom he might have been considerably less great.

Tune into a Tour stage on the Outdoor Life Network, and you will see Bruyneel, the field general for the Postal team, chasing Armstrong in his follow car. Cycling is as deeply intricate as it is fast-moving, a game of high-speed improvisational chess, and Bruyneel is the one who moves the pieces. Each year, Bruyneel studies the Tour route, determines which stages Armstrong should try to win, organizes pre-Tour training camps, and selects the eight other riders who make up the team. During the Tour itself, each morning before every stage Bruyneel announces the team strategy and appoints roles to the riders.

As they race, it's Bruyneel's job to control the pace and tactics of his riders, while he also keeps track of the rest of the field, nearly 200 others. He gives orders in five languages over his radio, while following the race action on a small mounted TV on his dashboard. He maneuvers riders, launches attacks, and fends off the attacks of others, all in the name of getting Armstrong to the finish line safely and in front. He also manages a staff of mechanics, marshalling food, water and mechanical aid from that careening car.

Bruyneel does all of this with a demeanor that is impassive, almost toneless. Bruyneel is stolid Belgian with a shock of brown hair, a cleft chin, and when he talks to Armstrong he has a habit of mixing words from several languages into a kind of cycling pidgin. He and Armstrong are not particularly alike: Armstrong is excitable, aggressive and high spirited, while Bruyneel is imperturbable and methodical in crises and during a race is serious to the point of being deadpan. It's a trait Armstrong likes to play with.

The joking term on the Postal team for feeling good on the bike is "no chain," meaning, pedaling feels effortless. Two years ago, in the midst of a rather tense Tour stage, Armstrong got on his radio and called Bruyneel.

"Uh, Johan, I need to check something on my bike," he said.

Bruyneel began barking out orders, organizing the other riders and mechanics to go to Armstrong's aid.

"No, no, I don't need all that," Armstrong said. "I just need confirmation of something."

"What?"

"I need to know if there's a chain on this bike," Armstrong said. "Because I can't feel it."

There was a pause, and then Johan's voice replied, crackling in the radio.

"You [expletive] . . .," he said, as the team broke up in laughter.

But accompanying Bruyneel's impassivity is a tactical flair that's almost flamboyant. It was Bruyneel, for instance, who devised their famously dashing strategy on the legendary L'Alpe d'Huez in 2001. The Postal team was weakened by injuries, and Armstrong was vulnerable, trailing leader Francois Simon by 35 minutes. Bruyneel came up with the following ploy: He told Armstrong to feign fatigue and hang at the back of the pack, saving himself, while tempting the other riders to ride harder to lose him. Meanwhile he prepared a surprise attack. Bruyneel himself played a part, telling television announcers he couldn't understand what was wrong with Armstrong and the cyclist would just have to "try to survive." The other riders took the bait: They wore themselves out trying to put time between themselves and Armstrong.

Bruyneel, in his mixture of English and Flemish, instructed Armstrong to bide his time and be ready at the foot of the L'Alpe d'Huez, the legendary mountain climb of 12 miles with 21 switchbacks.

"When we get to the bottom of L'Alpe d'Huez, that's when you go," he said. "And when you go, you go volleback."

Volleback is the Flemish term for "floor it."

"Volleback," Bruyneel said again, "you got it?"

"You're gonna see volleback like you've never seen volleback," Armstrong promised.

At the foot of the mountain, Armstrong surged. His rivals were too tired and stunned to respond. Armstrong won the stage by a crushing margin, and the blown-apart field never recovered or seriously challenged him again.

The irony is that Bruyneel was a cyclist who craved greatness in his own right but lacked the physical ability to make an enduring mark on the sport. When he retired in 1998, he had a reputation as a rider of limited journeymen talent but great resourcefulness who knew how to beat more powerful competitors with hard work and wits, and won two Tour stage victories.

There are two famous stories about Bruyneel in the Tour de France. In 1995, he outdueled the great Miguel Indurain in a spectacular finish into Liege. Bruyneel rode just behind Indurain's wheel, stalking him, before suddenly pulling around and beating him in a sprint to the line.

In 1996, Bruyneel took a horrendous spill in the Tour on the Cormet de Roselend in the Alps. Near the bottom of a rain-slickened 4,000-foot descent, he skidded out on a turn, struck a stone curb and was catapulted over a cliff into some bushes a hundred feet down an incline. Bruyneel climbed on his hands and knees through the brush and rocks up the face of the cliff, got back on his bike, and finished the stage.

Through Armstrong, Bruyneel says, he has finally been able to fulfill his frustrated Tour ambitions, marrying his determination and tactical skill to great talent. "For me, it was like trying to make something happen that I always wanted, but physically I was not able to do it," Bruyneel said by phone from France. "I knew how to work for it, but if you don't have the physical capacities, you can't do it. Lance has those capacities."

The same is true in reverse: Through Bruyneel, Armstrong has acquired discipline and a mind for strategy that's enabled him to fulfill his talent. Prior to his bout with cancer, Armstrong was a heady but not especially dedicated cyclist who tormented his coaches with foolish headlong charges and uneven training habits. Bruyneel regarded him as many others in cycling did, as a great young rider capable of explosive rides but wasteful of his abilities and lacking the focus to be a Tour contender. "I remember him from when I was a rider," Bruyneel says. "I saw in him a big talent. For one day, he could be very good."

When Armstrong returned from the disease, everything had changed: Armstrong had become an almost fanatically dedicated rider, determined to make the most of what he had left. He was a coach's dream. "I always thought that if you worked with a powerful athlete like that in the right way it had to be possible to perform over three weeks," Bruyneel says, and that's what they set out to do. Bruyneel made Armstrong something he had never been, a prepared and efficient rider. He convinced him to spend winters in training camps in the Alps and Pyrenees. He altered his pedaling cadence. They went into wind tunnels, seeking better positioning to save fractions of seconds. They experimented with new bike technologies. "He is willing to not leave anything undone," Bruyneel says.

Coach and rider found that their differences proved to be the perfect complement to each other: Bruyneel's tactical intelligence and Armstrong's extraordinary will; Bruyneel's gift for preparation and Armstrong's physical capacity to execute any plan. For all of their differences in personality, they have an effortless understanding, able to finish each other's thoughts. "A lot of times we think the same way, and it's difficult to explain exactly why," Bruyneel says. "We don't have a lot of disagreements. We're passionate about the same things, the work, and the details."

What they share is a tireless work ethic, mutually inexhaustible ambition, and a vision: Bruyneel saw more in Lance Armstrong than Lance Armstrong saw in himself. In a way, what Bruyneel has given to Armstrong is the greatest gift, himself. Together they've created cycling lore.

Sally Jenkins has written two books with Lance Armstrong.

Lance Armstrong, right, toasts Coach Johan Bruyneel on way to winning Tour de France in 2002. Bruyneel has been a major force behind Armstrong's success.