Stand-up comedians succeed on the illusion that they're perpetually funny guys who just happen to wander in front of an open mike.

If you want to preserve that happy illusion, don't go see the documentary "Comedian."

If you want to see the reality behind Jerry Seinfeld and other successful stand-ups, if you want to see fearful, jealous, paranoid, insecure, desperate craftsmen who labor for years to create an hour of funny material, then by all means, see "Comedian."

This documentary (shot on video by director Charles Steiner) follows Seinfeld's attempt to craft 60 minutes of good, all-new material to replace the old routine that made him, in the early '90s, the country's funniest stand-up before he created the hit series "Seinfeld."

When the series ended, Seinfeld retired his old material on an HBO special, and made the Sisyphusian decision to start all over again - developing and shaping new material into a brand new act.

This movie prompts wide-eyed shock from fellow comedians ("Comedian" is full of cameos by Chris Rock, Bill Cosby, Jay Leno, and others) who are in a position to know just what Seinfeld is giving up, and how much work goes into honing a new act.

For Seinfeld, the work starts slowly, fitfully and almost anonymously - he takes untried material to unbilled appearances at small clubs. It's humbling and invigorating - he flubs lines, forgets material, constantly checks his note cards. His reputation earns him automatic ovations, but when the applause dies down, he has to be funny, and in the early stages he fights through hecklers and skeptics to find the jokes that work, to rethink those that don't.

In Seinfeld's candid conversations with other comics, you can see how much stand-ups loathe this painful process, how balefully they regard the audience, how much labor goes into a joke - like luck, it's 90 percent perspiration.

There is also a certain grace to Seinfeld's moments in the film - he has wisdom, patience, the self-possession of a veteran performer - and despite the raised hackles that are a natural to any competitive endeavor, you see he also enjoys a sense of camaraderie with fellow comics.

His approach contrasts amusingly in "Comedian" with that of upstart comic Orny Adams, a rapacious young stand-up in whom fear of failure and desire for success clash like Bush and Hussein.

Seinfeld spends several grueling months building a new routine, but he eventually glides back to the top in his private jet. Adams, meanwhile, claws his way by glomming on to influential people, sparring angrily with fellow comics and finally sweating his first appearance on "Letterman," while Seinfeld returns as a conquering hero.

When Adams finally wins the allegiances of a powerful agent, it comes with a sobering prediction.

"You'll succeed," the agent says, "but you'll never be happy."

And we know it's true.

With its starkly contrasting presentation of competitive motivation, "Comedian" is like the stand-up version of "Chariots of Fire." Only funnier.