(FORTUNE Magazine) – By 9:10 a.m., John "Winter" Smith--just Winter to those who know him--had already been up for three hours, visited four Starbucks, eaten one Starbucks doughnut, and downed a Starbucks DoubleShot espresso and 12 ounces of regular Starbucks coffee. He's jittery, but he's still on his game: Standing at the counter of Starbucks No. 5 for the day, an unremarkable strip mall location in Scottsdale, Winter realizes something is amiss. "These cards are different!" he says, staring at the store manager's business card, which he's grabbed from a stack at the register. "I haven't run into any other cards across the country that have this on the back." He analyzes the flip side, which uses an acrostic of the word "partner" to spell out why working at Starbucks is so rewarding. Holding the card up to the manager--who offers a confused smile--Winter continues, "And the card stock, it's thinner." He then asks for, and receives, a complimentary half-cup refill of a Starbucks cup he's brought with him, darts in and out of the bathroom, snaps a photo of the store, stows the camera in his car, and declares, "That's it here."

But really it's just the start. Winter is on a mission to visit every Starbucks in the world. On this day alone, he has mapped out four more stores around Phoenix and two in El Paso that he needs to hit. A contract computer programmer, Winter works just enough to fund his obsession, for which he has laid out specific rules: He stops only in Starbucks that the company owns--eliminating the more than 3,000 licensed spots in places like airports and grocery stores--and he has to drink caffeinated coffee in each. In the seven years that the 32-year-old has been on his quest, he's been to 4,122 stores in North America (including some that have since closed), 114 in Britain, and 53 in Japan. Starbucks operates 4,025 stores in the U.S. and 846 internationally. So Winter is doing pretty well. Except for this one problem: The company opens an average of 10.2 new, company-operated Starbucks a week around the world and has no plans to slow down.

Neither does Winter. On the fringe of society, there have always been thrill seekers looking to achieve immortality by pushing through society's dark borders. Ernest Shackleton wanted to show that Antarctica could be traversed; Charles Lindbergh demonstrated that flight could be a competitive form of transportation; Neil Armstrong set foot on the moon. Today it's Winter's turn: As Starbucks continues its unstoppable, Frappuccino-fueled global takeover, he seems to be trying to show that someone can move even quicker. "I can always visit them faster than they can build them," he says in his robotic, slightly nasal monotone. "That's just a numerical fact." But it won't be easy. As an alarming headline read in none other than The Onion a few years ago, NEW STARBUCKS OPENS IN REST ROOM OF EXISTING STARBUCKS.

"Hello. Is the manager or shift supervisor here?" asks Winter. He's stepped into another Phoenix-area hit, the Starbucks on North Hayden Road in Scottsdale, which opened in February. A "partner" at the counter points him toward a woman walking out from the back.

Winter hands her his calling card: a coffee-stained manila folder that holds a stapled, equally coffee-stained printout of an Associated Press story written about him. As she skims the article, he launches into his speech. "For the past seven years, I've been on a mission to go to every Starbucks location in the world ..."

Before he can finish, a worker with spiked blond hair behind the counter yells, "Oh, my gosh, I know you!" Winter, stunned momentarily, asks the barista if he's seen the website or possibly a clip on the Food Network. The barista shakes his head. Winter had long ago visited the store where the employee used to work. That leads to small talk about Phoenix-area Starbucks.

Winter soon cuts it off. There are quotas to meet and self-imposed rules to follow. "For my visit to count," he tells the manager, "I have to drink coffee. Could you offer me half a cup of coffee? Only half." She does, and Winter speeds out the door.

The details are hazy, but as Winter recalls it, the idea for the quest was born while chatting with employees at his Starbucks hangout in Plano, Texas, in 1997. The topic of the chain's growth kept coming up. "The idea randomly popped into my mind," he says. "What would it be like to visit every Starbucks? Would I be the only one? Could I do something unique?" Late that summer he flew to Minneapolis for a rock concert and made a point of visiting a few Starbucks. He was hooked.

A normal trip works like this: Winter maps out a route and loads his Honda Civic --bought for $4,000 on eBay--with a pile of Starbucks T-shirts, CDs (though the car lacks a CD player or even a tape deck), books, a computer, an egg-crate mattress, and, for protection, a baseball bat. He blazes through the stores (hitting a record 28 in one day on a swing through Portland, Ore., in 1999). At night he tries to find a Wal-Mart parking lot, where he can sleep in the Civic undisturbed. The car has no air conditioning and smells of stale coffee.

It isn't all fun and games. "After about four stores, the coffee loses all taste," says Winter, who's unconcerned about any long-term effects of so much coffee. "It doesn't taste good at all--I'm not enjoying drinking it. After an extreme number of stores, I have to wash out the taste with water after every sip because it's starting to make me sick."

Starbucks hasn't exactly embraced Winter. A few years ago it sent him a note --along with a copy of founder Howard Schultz's book and some mugs--but has been quiet since. In a re-cent statement, a Starbucks spokeswoman wrote, "Winter demonstrates a great enthusiasm for the Starbucks Experience," and called his passion "flattering."

Winter's passion does have a way of attracting others. "I think what he's doing is great--very admirable," says Jodi Morgan, a 27-year-old who has been in an online relationship with Winter since January. After stumbling onto Winter's site, she e-mailed him to let him know that a new Starbucks had opened in her town, Springfield, Ill., last summer. Winter wrote back that it wasn't a real Starbucks--it wasn't owned by the corporation. The relationship blossomed. In early June they met face-to-face. Morgan says Winter was "more jittery" than she had expected--but then, she notes, he'd already been to five Starbucks by the time they met.

Winter explains that no matter how things go with Morgan, his life is Starbucks. "There's no such thing as completeness," says Winter, who double-majored in philosophy and computer science at the University of Texas at Austin. "There's no way to be finished unless Starbucks goes out of business or changes its name. Those are two scenarios under which I would essentially be done, but there's really no such thing. The best I can hope for is to keep up. I can't foresee myself stopping." Winter stares into the bright Phoenix sun. "It's too rewarding an experience."

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