STILL HOLDING his paper bag stuffed with his CL-Ones and lottery tickets, Milch bypasses the set and enters his empty trailer with Steve Hawk. While Hawk takes a seat on a sofa, Milch, who has a bad back, lies on the trailer's floor, and the conversation turns to surfing, drugs, language, sex, the world's interconnectedness, and anything else that pops into Milch's prodigious mind.

A 1966 graduate of Yale University, Milch studied English with poet and novelist Robert Penn Warren. He earned an M.F.A. in writing at the University of Iowa and taught at Yale before breaking into TV as a scriptwriter on Hill Street Blues, in 1982.

Milch still comes off like a hip, approachable professor. He regularly entrances the writers, producers, interns, and anyone else around him with extended soliloquies that quote the wisdom of "Mr. Warren," Herman Melville, Ezra Pound, Albert Einstein, Lao-tzu, The Godfather, and Joseph Conrad. One of his favorite topics is authenticity. "Any special world is liable to be done wrong," he says.

To keep the authenticity quotient high in John from Cincinnati, Milch has surrounded himself with people who not only know beach culture but live it. In addition to Hawk, Van Holt, and "surf-noir" novelist Kem Nunn, John's co–executive producer, the show's surfers include former women's pro Keala Kennelly, who plays an employee at the Yosts' shop. Greyson Fletcher, who portrays Shaun Yost, is the grandson of legendary surfer Herbie Fletcher (a show consultant) and son of Christian, a pioneer of aerial maneuvers. Renowned big-wave rider Brock Little coordinates the water scenes—shot by celebrated surf-film cinematographer Sonny Miller—with pro-surfing stunt doubles John John Florence, Shane Beschen, and Dan Malloy. All of which adds up to an amazing sense of verisimilitude.

In the rough cut of episode one, Mitch Yost catches a small, decidedly average wave—not a grinding, Pipeline tube like the one that opened Hawaii Five-O—and gracefully cross-steps to the nose. It's smooth surfing; realistic, not showy. The actors who know what they're doing, like Van Holt, are filmed paddling their own boards; the magic of editing then blends in the shots of professional stunt doubles once their characters take off on waves.

Surfspeak is used, but it's current (no "Cowabunga!") and natural. Meanwhile, you can almost smell the coconut surf wax in the Yosts' shop, which perfectly captures the cramped, cluttered stores that dot the California coast.

"When you're telling a story that involves surfing, the hardest thing to capture is the essence of it," says Milch. "You have to approach that quietly. I'm never going to know what it feels like to surf. But I think I've had analogous experiences. I shot dope for a long time, and in some respects, not the enterprise but the result is the same. You feel a kind of oneness and lack of desire to be anywhere else, and a yearning that the state you're in can be perpetual."

But Milch stresses that he's serving a story, not a sport. "I'm not a supplicant at the altar of surfers as arbiters of authenticity," he says. "Which is very different from saying I don't care about getting it right. I care, but not to please surfers. When I write, there are only five or six people whose nods of approval I care about. But all of them are dead."

As Milch sees it, surfers may complain about how they're portrayed, but they also delight in the twisted interpretations of their culture by outsiders—in the ways "the philistines" get it all wrong. "I find it kind of tedious that what is essentially a solitary enterprise is supposed to be ‘gotten right,' " he says. "It speaks to what I feel is a perpetual adolescence, the great pleasure that surfing has always taken in being gotten wrong."

He's jamming now, and he cranks his philosophical amp to 11. "Now I'll give you a challenging thought," he says. "A significant part of surfing is shame-based behavior."

"That's fucking bullshit," says Hawk, pretending to get angry. "I'm leaving."

"[Overcoming the belief] that it's an activity unworthy of an adult is the constant battle for the adult surfer," Milch says, pointing out that surfers "of a certain age" see surfing as spiritual, and the ocean as a church. "A lot of defiance is shame-based—the uneasiness that surfers feel: ‘Am I a fucking kid?'"

"I can come up with a thousand ways to justify it," says Hawk.

"The rationalization of junkies is exactly the same," says Milch. "‘Did I never grow up?'"