For pot smokers with careers to protect, the license to ward off cops (and bypass dealers) is a strong incentive to buy doctor’s notes. “I’m too old to start a police record,” says “Chris,” a 35-year-old e-commerce senior developer. “A lot of my close friends now have the get-out-of-jail-free card.”

“It used to be that physicians only wanted the wheelchair patients,” says Jean Talleyrand, 39, an Ivy League–educated pot doc in the Bay Area. “But now that the movement has gained traction, the landscape is different. A surprising number of our patients are highly successful young professionals who would simply rather sidle up to a bong than a bottle.”

Talleyrand was serving impoverished patients in a San Francisco public-health clinic when he decided to open up his first MediCann evaluation clinic in late 2004. “I knew that marijuana was a safe, herbal alternative to Ambien, Valium, and Vicodin,” he says. With pot laws now on the books in 10 other states, including Alaska, Colorado, Rhode Island, and Maine, Talleyrand is looking less like a renegade and more like a shrewd businessman. In two years, MediCann has become a statewide chain that’s written $135 recommendations for 54,000 patients.

Marijuana is the largest cash crop in California, worth an estimated $13.8 billion a year—nearly double the combined value of grapes and vegetables—according to statistics released in December by the Bulletin of Cannabis Reform. (The value of the annual marijuana output in America is estimated at more than $35 billion.) In Los Angeles, the number of cannabis clubs has skyrocketed from a handful in 2004 to at least 125 today. “Pot clubs are the fastest-growing industry in Southern California,” says “Alex,” 32, who owns several of them.

With such explosive demand comes a swarm of registered “compassionate caregivers.” Not long ago, “Tyler” was an East Coast real-estate investor with a six-figure salary, a new house, a girlfriend, and a dog. At first he was reluctant to chuck his career “to become a drug dealer,” as he puts it, but after determining that the business was both legitimate and lucrative, he rented out his house, ditched his girlfriend and his career, and headed west in a U-Haul with his dog. “I wanted to stake my claim in the new California gold rush,” he says.

Today the 28-year-old medical-marijuana provider drives a new luxury sedan and lives in a spacious loft in downtown San Francisco. This savvy entrepreneur seems relatively at ease considering his career is at odds with federal law. He retains two lawyers and an accountant and steadfastly plays by the state’s rules. Last year, Tyler declared an income well into the six figures with the IRS. “I didn’t hear them bitching about that,” he notes wryly.

Tyler thinks of himself as a craftsman. “What I do is every bit as artisan as winemaking,” he says. Unlike winemakers, though, licensed pot growers must limit their output. (In San Francisco, one person may cultivate 99 plants.) And as more growers saturate the market with better pot, Tyler has had to cut the price of his potent Trainwreck strain to $3,500 a pound, down from $4,000 a couple of years ago. The business is ruthless: “It’s all about who has the new hash-extraction method, the new hybrid strain of Sour Diesel, the new shit nobody else has their paws on,” he says.