Michael Pollan wrote the right book at the right time.

In April, Pollan, a journalism professor at the University of California, Berkeley, published "The Omnivore's Dilemma," an interrogation of both the industrial food system and the fast-growing organic sector that was supposed to be its alternative.

He couldn't have known what would follow.

This year, organic food finally went mainstream, manufactured by Kraft and available on the shelves at Wal-Mart -- while at the same time a wave of news reports pointed out that, image to the contrary, organic supermarket food usually isn't grown by a small local farmer.

That was quickly eclipsed, however, by two more prominent events:

• A summer of high oil prices drew attention to the huge energy demands of the U.S. food system's reliance on synthetic fertilizers and long-distance shipping.

• September's nationwide E. coli outbreak in bagged spinach spotlighted the vulnerabilities of highly centralized food chains.

Pollan's book foreshadowed these developments. And he became suddenly -- and somewhat reluctantly, he says -- the nation's most articulate champion of alternative food systems, ones that advocates argue are more regional, seasonal and personal -- and more flavorful, safe and environmentally sustainable.

How big has Pollan become? He says he turns down five speaking requests a week. After a pointed public exchange with Pollan in June, the chief executive of Whole Foods Market vowed to buy more produce from small local farmers. Berkeley food diva Alice Waters says Pollan should run for president. And he showed up on Comedy Central's "The Colbert Report," where host Stephen Colbert stumped him by asking what he would eat for his last meal.

"The culture wants to have a conversation on these issues. You have to speak while it's listening," Pollan said during an interview in his basement office on the Berkeley campus.

One speech Pollan didn't turn down -- the request came in before the book was published -- is the one he will deliver Wednesday at the University of California, Davis. "The Omnivore's Dilemma" is the subject of the annual campus community book project, and Pollan's appearance is the crowning event. The book, the subject of campus discussions all quarter, is being taught in 25 courses.

While local food is gaining popularity nationwide, the movement has particularly deep roots in the Davis area, which has hosted a farmers market for 30 years. In the last national agricultural census, in 2002, Yolo County led the nation in direct-to-consumer sales from small farms. The resurgence of small, local farms also has made it feasible for chefs to incorporate the local bounty into their menus.

"Local food is of much more interest than it was two or three years ago," said Jim Mills, sales manager at Produce Express, a West Sacramento distributor that sells fruits and vegetables to 1,300 restaurants in the region.

"You'd kind of have to keep your head down and your eyes shut to ignore it all."

Pollan, 51, certainly didn't come out of nowhere. He's the former executive editor of Harper's magazine, a contributor to the New York Times Magazine for nearly 20 years and the author of three previous books, including the 2001 best-seller "The Botany of Desire."

Pollan built "The Omnivore's Dilemma" around a simple conceit: He'd design four distinct meals and then report on what it took to put them on his table. He writes in the first person, casting himself as a curious and well-read gastronome on an investigative mission.

The meals:

• Fast Food: a McDonald's cheeseburger made from corn-fed feedlot beef (and eaten on the freeway, at speed).

• Organic: an all-organic dinner of chicken and asparagus bought from Whole Foods Market.

• Grass-Fed: a chicken raised on a small mixed-livestock farm on which Pollan worked.

• Personal: a meal that he hunted and gathered himself, a wild boar shot in Sonoma County, with mushrooms collected in the Eldorado National Forest.