For Seinfeld, whose worth Forbes estimated in 2010 to be $800 million, his touring regimen is a function not of financial necessity but rather of borderline monomania — a creative itch he can’t scratch. “I like money,” he says, “but it’s never been about the money.” Seinfeld will nurse a single joke for years, amending, abridging and reworking it incrementally, to get the thing just so. “It’s similar to calligraphy or samurai,” he says. “I want to make cricket cages. You know those Japanese cricket cages? Tiny, with the doors? That’s it for me: solitude and precision, refining a tiny thing for the sake of it.”

When he can’t tinker, he grows anxious. “If I don’t do a set in two weeks, I feel it,” he said. “I read an article a few years ago that said when you practice a sport a lot, you literally become a broadband: the nerve pathway in your brain contains a lot more information. As soon as you stop practicing, the pathway begins shrinking back down. Reading that changed my life. I used to wonder, Why am I doing these sets, getting on a stage? Don’t I know how to do this already? The answer is no. You must keep doing it. The broadband starts to narrow the moment you stop.”

Seinfeld likes pressure. He describes doing live comedy as “standing against a wall blindfolded, with a cigarette in your mouth, and they’re about to fire.” His objective at Gotham was piecework. “A lot of what I’ll be doing tonight are tiny things in my bits where I’m looking for a little fix, where something isn’t quite smooth,” he said. “A lot of stuff I do out of pure obsessiveness.” One bit began with the observation that “tuxedos are the universal symbol for pulling a fast one.” “That line works,” he said. “But I want to get from there to a point about how the places where you see tuxedos are not honest places — casinos, award shows, beauty pageants, the maitre d’ — all these things feel shady.” He added: “But I’ve been having trouble getting the audience to that. I’m trying to bring that to a punchline.”

Seinfeld likens his fine-bore interest in jokes to his longstanding infatuation with Porsches, of which he owns “a few dozen.” “People ask me, Why Porsches? A lot of it is the size, same as with bits. The smaller something is, the harder it is to make, because there’s less room for error.” In high school he took shop classes, even after a counselor told him that collegebound kids didn’t need to, because he wanted to know how machines fit together. “I have this old ’57 Porsche Speedster, and the way the door closes, I’ll just sit there and listen to the sound of the latch going, cluh-CLICK-click,” Seinfeld said. “That door! I live for that door. Whatever the opposite of planned obsolescence is, that’s what I’m into.” Mark Schiff, a veteran club comic and one of Seinfeld’s oldest friends, told me: “He’s a scientist. When you watch him, he’s in the lab, concocting. I feel that way, too, to a degree, but with him every little nuance is so valuable.” Sarah Silverman, who has shared bills with Seinfeld and long admired him, agrees: “Whereas most comedians are lazy bastards, he’s the ultimate craftsman.”

Developing jokes as glacially as he does, Seinfeld says, allows for breakthroughs he wouldn’t reach otherwise. He gave me an example. “I had a joke: ‘Marriage is a bit of a chess game, except the board is made of flowing water and the pieces are made of smoke,’ ” he said. “This is a good joke, I love it, I’ve spent years on it. There’s a little hitch: ‘The board is made of flowing water.’ I’d always lose the audience there. Flowing water? What does he mean? And repeating ‘made of’ was hurting things. So how can I say ‘the board is made of flowing water’ without saying ‘made of’? A very small problem, but I could hear the confusion. A laugh to me is not a laugh. I see it, like at Caltech when they look at the tectonic plates. If I’m in the dark up there and I can just listen, I know exactly what’s going on. I know exactly when their attention has moved off me a little.

“So,” he continued, “I was obsessed with figuring that out. The way I figure it out is I try different things, night after night, and I’ll stumble into it at some point, or not. If I love the joke, I’ll wait. If it takes me three years, I’ll wait.” Finally, in late August, during a performance, the cricket cage snapped into place. “The breakthrough was doing this”— Seinfeld traced a square in the air with his fingers, drawing the board. “Now I can just say, ‘The board is flowing water,’ and do this, and they get it. A board that was made of flowing water was too much data. Here, I’m doing some of the work for you. So now I’m starting to get applause on it, after years of work. They don’t think about it. They just laugh.”

Seinfeld’s work habits were stringent from the start. Studying communications and theater at Queens College, he arranged an independent study in stand-up, trying club sets, analyzing others’ sets and writing a 40-page paper. When he scored his first appearance on Johnny Carson’s “Tonight Show,” in 1981, he practiced his five-minute set “200 times” beforehand, jogging around Manhattan and listening to the “Superman” theme on a Walkman to amp up.

We’re accustomed to the cliché of the stand-up as sad clown: a racked soul on a dim stage, salving psychic wounds, craving approval. When audiences yell, “I love you,” at Seinfeld, he likes to reply, “I love you, too, and this is my favorite type of intimate relationship.” He told me: “That’s the wiring of a stand-up. This is my best way of functioning.” But he sees himself more as exacting athlete than tortured artist. He compares himself to baseball players — putting spin on the ball as it leaves his fingers, trying to keep his batting average high — and to surfers: “What are they doing that for? It’s just pure. You’re alone. That wave is so much bigger and stronger than you. You’re always outnumbered. They always can crush you. And yet you’re going to accept that and turn it into a little, brief, meaningless art form.” He said: “I’m not filling a deep emotional hole here. I’m playing a very difficult game, and if you’d like to see someone who’s very good at a difficult game, that’s what I do.”