For Bil Keane, being a family man has paid off.

While other artists may have to plumb their souls for inspiration, he only had to observe the goings-on in his own home. The result: one of the most popular, long-running (and uncynical) daily newspaper cartoons.

When Keane began "The Family Circus" in 1960, he worked in a studio attached to his Paradise Valley, Ariz., home, and his kids were small and underfoot. Consequently, "I enjoyed drawing the foibles and funny situations in a typical family with small children."

At the time, there already were a number of successful strips stressing the comic aspects of family life -- "Dennis the Menace," started in 1951 by Hank Ketcham; Charles Schulz's "Peanuts," begun in 1950, and "Blondie," created in 1930 by Chic Young -- but Keane found that he had something different.

"I realized that the cartoons that gathered most comment and that people really seemed to love were the ones that weren't necessarily funny, but had a typical situation they could identify with."

An early Keane cartoon showed Jeffy toddling into the living room late one night while Mommy and Daddy were watching TV. Jeffy: "I don't feel so good. I think I need a hug."

Letters flooded in, says Keane, 61. "I realized it hadn't been done in cartoon form before -- where somebody touched on those tender moments. Then I sought them out."

The idea for the strip came when the then-36-year-old Keane was ending a 15-year stint as staff artist with The Philadelphia Bulletin newspaper and moving west to launch a new career as a syndicated cartoonist.

"I called the feature 'The Family Circle,' and drew it in a circle," he says, "because I felt it was distinctive and fit right in with the mood." It focused on the daily life in a family populated by Mom, Dad, Billy, Dolly and Jeffy.

The strip went originally to 19 newspapers. Within six months, Keane found himself threatened with a lawsuit. Family Circle magazine said that was their title and insisted that Keane change the name of his feature. "At that time, with just a few newspapers, running into a long legal battle wasn't worth the money to my syndicate the Register and Tribune Syndicate, Des Moines , so I changed the 'le' to 'us' and made it 'The Family Circus.' "

Over the years, Keane continued using his own family -- wife Thel, daughter Gayle, and sons Neal, Glen, Chris and Jeff -- as subjects for his "paper" family. In fact, he sometimes mixes them up. "I live with these situations and these characters, and I get to love them so much that Billy, Dolly, Jeffy and PJ the baby , although based on our own children, are separate to me."

They even show up in his dreams, Keane admits, along with his and Thel's own children. "I can't separate the real-life family from my family that I have created on paper."

Keane mixups have occasionally caused some real-life confusion: In 1962, he realized that Jeffy, though he was only a toddler, was too old for some of the baby situations -- diapers, baby food, high chair. Keane needed a newborn, an infant.

"My wife was outside the studio working in her garden, the flower bed. I thought it would be a good idea to show Mommy pregnant in the cartoon and then have the baby born.

"I ran out of the studio and said, 'Thel, what would you think of adding a new baby to the family?' She said, 'Well, it's all right, but let me finish the weeding first.' PJ was born in the daily cartoon on Aug. 1, 1962. It's short for Paul John."

Some of the cartoons come from Keane's own experiences as a youngster, growing up in Philadelphia. In one strip, Jeffy is upstairs sleeping in his bed when Mommy and Daddy raise their voices in an argument. He wakes up, sweating and on the verge of tears. In the next panel, they make up and Jeffy calms down. In the final panel, they kiss and Jeffy is asleep again.

Says Keane: "I can remember lying up in my bed and hearing my mother and father arguing about something and just being frozen, where I couldn't get to sleep and I was perspiring. The world was wrong at that point, until I heard their voices back to normal, and then you realize everything is normal and you go back to sleep."

Years later, when Keane's son Jeff, now 26, was helping him work on the just-published The Family Circus Album: A 25th Anniversary Celebration (Fawcett Columbine, $7.95), Jeff told him: "Dad, I thought you drew that cartoon about me, because I remember that myself."

Our children and grandchildren are different from when we were small, notes Keane. Different in language, attitudes and knowledge, but "in their innocence and frankness, in saying the wrong thing at the wrong time, in mispronouncing a word or innocently evoking an emotion such as nostalgia or love," the generations don't change.

That, says Keane, is another reason he doesn't just go for the funny bone. "Sometimes I'll throw out cartoon ideas that are funny because they're a little too exaggerated, too trumped up, and I'll substitute something that's more tender, that will cause a tear in the eye or a tug at the heart."

His readers apparently approve, and they let Keane know when they don't. He averages 100-150 cards and letters each week and tries to personally answer "as many as I can."

"Family Circus" now appears in around 1,100 newspapers, with an estimated 50 million-plus readers weekdays and Sundays. (A cartoonist with that circulation could expect to make roughly $400,000 a year from syndication and licensing.)

And Keane has had his share of personal recognition, perhaps capped last year when his peers voted him winner of the National Cartoonists Society's Reuben Award as "Cartoonist of the Year." Twice previously they had elected him president of the society.

That the feature continues to grow in popular acceptance can be seen in its most recent growth: Somewhere between 200-250 newspapers have been added to its client list over the last two years. "If a new comic strip gets 50 to 75 sales in its first year or so, you're doing a pretty good job," says Register and Tribune Syndicate executive Tom Norquist. "To add as many as Bil has after this long is unheard of.

"The reason that any strip endures for 25 years is that it finds a niche. You have to have some kind of hook to make it through the changes and cycles that the country goes through."

The Keanes' real-life children are now all grown. Chris, 28, is a Santa Barbara marine biologist; Glen, 30, a Los Angeles free-lance film animator; Neal, 33, a Los Angeles computer engineer; Jeff, 26, a Los Angeles actor; Gayle, 35, owner and operator of BloominGayle's, a Sacramento plant shop. Cartoon inspiration now often comes from four grandchildren.

And the "paper" kids are doing fine. In fact, they've hardly aged. "I had PJ grow on a slow-motion basis to 18 months old," explains Keane, "so Jeffy grew to be 3. Dolly is 5 and in kindergarten. Billy went from first to second grade. He's 7 years old.

"I figured 'If I keep this up, in no time, Billy's going to be 13 by our 25th anniversary,' so I froze them at those ages. Now, if I could just get that to work for myself, I'd be home free."