Most artists try to reinvent themselves throughout their careers. They have their Blue Periods, their Cranky Periods, their Maalox Moments of the Soul. They've been blocked, bested by the demons that dwell in their innermost psychic sanctums. They've looked at the face of God and said "Huh?"

Then there's Rob Reiner, who went from Meathead to moviemaker, from sitcom doofus to king of Castle Rock, his production company, but still returns again and again to his favorite subject: the story of himself.

"Except for 'This Is Spinal Tap' and 'The Princess Bride,' the movies I've made are extensions of something I've gone through or I'm experiencing. That's the only way I know how to tell stories," says the 52-year-old director, actor and political activist during a fly-by to promote his latest effort, "The Story of Us."

The seriocomic tale draws upon what he has learned in his 10-year-marriage to second wife Michele Singer, a photographer he wooed while filming "When Harry Met Sally . . ." in 1989.

Though the Reiners are happily married, he says, they've remained that way because they've carved out some time for themselves. And that is the message he delivers in "The Story of Us," a portrait of a marriage on the brink.

Bruce Willis and Michelle Pfeiffer star as a couple who have grown apart over 15 years of marriage and attempt a trial separation while their kids are away at camp. During restless nights and empty days, each thinks back to happier times: their first meeting, the births of their children, the night they did it on the kitchen table.

"Nothing cataclysmic happens. There are no car wrecks; there's nobody getting cancer," says Reiner of the love story, co-written with Alan Zweibel and Jessie Nelson, who also drew inspiration from their marriages. "It's what happens on a day-to-day basis, and that's what we wanted to examine.

"You see so many movies about people meeting and falling in love and people going through the pain of a divorce, but few deal with the day to day, the wear and tear, the ins and outs of marriage. With getting the kids to school, play dates, soccer games. . . . You can drift apart even if you have a good marriage," observes Reiner, the father of two sons and a charming 21-month-old daughter.

She must have inherited her mother's temperament, because Reiner says he was a moody and shy child who showed no inclination toward comedy while growing up in the Bronx and New Rochelle, N.Y. He was born in 1947 in the proverbial trunk--"It was stuffy in there," he says, "so they poked some holes in the top."

Ba-dum-PUM.

In the world outside, he was overwhelmed and overshadowed by his famous father, Carl Reiner. By the early '50s, the elder Reiner was all wrapped up in "Your Show of Shows"--and apparently he wasn't exactly Superdad.

Of course, Rob resented the guy. But that's long over, he insists, having spent "millions of hours in therapy" exorcising his anguish. Besides, he later tapped into those experiences in "Stand by Me" (1986), an adaptation of a Stephen King novel that brought Reiner his first best-director nomination from the Directors Guild of America.

"It was the first time I made a film my father never would have made," he says. "A film that was a real extension of my personality. It was serious but had some humor in it. It was about a boy who felt his father didn't love him, and was insecure about his abilities, and was encouraged by his friends to pursue what he was good at, and that was being a storyteller. I was well aware that I was taking steps away from my father. And when the movie became successful, it validated me."

The unvalidated Reiner had spent seven years in the '70s as Michael Stivic, the whipping boy of Carroll O'Connor's Archie Bunker on CBS's "All in the Family." He enjoyed the experience but dreamed of making the transition to the sexier silver screen.

Surely there's something he misses from the sitcom days.

"Hair! I miss my hair!" he exclaims. The joke is perfectly timed, and why not? "I was exposed to the funniest people in the world. Those rhythms are embedded in my psyche." Mel Brooks, Sid Caesar, Howard Morris and Imogene Coca were frequent guests of the Reiners while he was a youngster. When the family moved to Beverly Hills, Rob spent his vacations on the set of "The Dick Van Dyke Show" and first began to learn what audiences found funny.

In "The Story of Us," Reiner puts all these influences to work in the role of Willis's best friend, Stan, a loud fellow who believes women are from Venus and men are from hunger. To that end, he urges the hero, a childishly self-absorbed novelist, to examine the part he played in the gradual decline of his marriage.

But Pfeiffer's character has become an uptight nag, as she discovers during her sabbatical from Willis and the children. Over time, she's become the "designated driver" of the marriage, the one who keeps the refrigerator filled and gets the kids to school on time. Willis is fun-loving and spontaneous, the one who wrestles with the kids and plays the clown at birthday parties.

What initially attracted them to each other has gradually driven them apart. They may live together, but they've failed to grow together and no longer know how to reconnect.

"I think of women as the protectors of relationships and the family, and of men as more childish, quite frankly," Reiner says. "It's a general statement, but that's the way I view men and women because that's the way I think I am. Women are always more organized, and the men are kind of flopping around like me.

"My wife, Michele, is definitely more organized. She's running the show. She's got things buttoned down. I have my work and stuff I do. She's definitely the designated driver. She's the one that's holding the family and marriage together," adds Reiner, whose first marriage, to actress-turned-director Penny Marshall, ended after 10 years.

"I revisit men and women over the course of my lifetime, examine the different stages of where I am in my own personal thing. 'The Sure Thing' [1985] was about young love; 'When Harry Met Sally . . .' [filmed after his breakup with Marshall] was about the dating scene. And now I'm married, so I'm revisiting the male-female relationships through that perspective. But I always go back to these kind of characters. In every one of my movies, the men and the women are all the same."

Although he's sampled many genres, the results are invariably mainstream. "I don't come from a film school background," says Reiner, who dropped out of UCLA to form a comedy troupe with such Beverly Hills High School chums as Albert Brooks and Richard Dreyfuss. "I don't think you should notice the camera work or the acting or the costumes or the set design. You should make some sort of seamless thing. . . . If the characters are well drawn, the movie will work."

It's always easy to identify with the characters in Reiner's films. Perhaps that's because he's more interested in the little picture than in the big one. "A Few Good Men" was ostensibly about military cronyism, the abuse of power and miscarriage of justice, but to Reiner the story was about a lawyer living in the shadow of a very famous father.

"In 'Misery,' " he explains, "the character was stuck in his creative life. I had experienced that in 'All in the Family.' At that time, people who came out of television were looked down upon and not thought of as people who could move into film. I wanted to become a director. That's what the hero of 'Misery' is trying to do, get away from something he'd been very successful at doing, to do something that's much more meaningful and personal. But the audience is going to get angry with him. He's frightened to go to another place for fear the audience will desert him."

Recently appointed to chair a California committee on early childhood development, Reiner splits his time between Castle Rock and his "government job." He's always been politically active, says the former hippie, but he's never been so visible.

So does he have higher political aspirations? Everybody else does.

"There are only three great government jobs," he says. "The mayor of a large city like New York, the governor of a big state like California or president of the United States. You can promote your own agenda, the things you are passionate about." But in a word, no. He's not interested right now, or so he says.

Yeah, sure, that's what Warren and Cybill probably said. Remember, Reiner did make a movie called "The American President."

CAPTION: Rob Reiner's new movie, "The Story of Us," reflects his views on marriage.

CAPTION: Directing Bruce Willis in "The Story of Us," Rob Reiner has come a long way since playing Mike "Meathead" Stivic on "All in the Family."