Every few months, Joan Crosby Tibbetts drives to McLean and gazes at the 18-room mansion where she lived in the 1930s. The place isn't for sale, but during upbeat moments she dreams of walking through the front door and buying it back.

The money for this purchase would come from, of all things, peanut butter. For the past 23 years, Tibbetts has poured her soul and dwindling resources into a quixotic campaign to wrest millions from the makers of Skippy peanut butter. The company, she argues, stole the name and look of Skippy's distinctive label decades ago from her father, a once-famous illustrator named Percy Crosby.

"I prefer the word `determined,' " says Tibbetts, a flinty 66-year-old grandmother who lives in a tiny Annandale apartment. " `Obsessed' has too many negative connotations."

At first glance, Tibbetts appears to be embroiled in a Dickensian trademark dispute and fighting a virtually hopeless cause. Long ago, however, her efforts became something much larger and a little stranger. Tibbetts is now struggling to rehabilitate a man she barely knew, a father who lost a fortune, his family and his mind after winning fame with a comic strip about a lovable young scamp in a polka-dot bow tie.

Largely forgotten now, Skippy was the Charlie Brown of his day, a fixture in scores of Depression-era newspapers and the inspiration for an Academy Award-winning movie. Dozens of manufacturers paid handsomely to license Skippy products, but no deal was cut with the one outfit that turned the name into lasting gold, a tiny California operation that had perfected a way to keep peanut butter fresh for months.

Skippy jars, now manufactured by Bestfoods, a New Jersey food giant, featured the slapdash red lettering and the white picket fence that regularly turned up in Crosby's beloved strip. By 1945, however, Crosby's Skippy trademark had expired and it was too late for him to win an infringement lawsuit.

Nonetheless, he died trying. Broken by divorce, an IRS audit and booze, Crosby spent the last 16 years of his life confined in the mental ward of a hospital, ranting about his enemies, filing lawsuits and denouncing "the steal of Skippy peanut butter." Hospital doctors described him as "forever litigious."

Fifty years later, only the names in this battle have changed. Tibbetts believes Bestfoods should hand over roughly $15 million, and after a series of legal setbacks she has taken her case to the public, launching a World Wide Web site, www.skippy.com.

But like everything else in this case, Tibbetts's corner of cyberspace has ended up in court. Bestfoods contends the site violates an unusual 1986 order that compelled Tibbetts to cease telling anyone the company lacks the legal rights to the Skippy food-products trademark.

On Friday, a judge in U.S. District Court in Alexandria will hold a hearing to determine whether Tibbetts must permanently take down the contentious parts of her site. Whatever happens, she isn't going quietly. There is a principle at stake, she says. And there is a childhood to recapture, those dimly recalled days when Tibbetts lived in a huge house with a celebrated family, one not yet torn asunder by liquor and madness.

"You've heard the term `fighting Irish?' " Tibbetts asked one recent afternoon. "He [Crosby] had some of that in him. So do I."

Tibbetts's living room is a jumble of aging Skippy mementos. There are ads for Skippy ice cream, a Skippy jigsaw puzzle, a red Skippy wagon -- all festooned with an irascible lad in droopy socks.

For years, he was unavoidable, and even today he can be found in unexpected places, such as the wall of the Palm, a Washington power lunch spot.

Skippy debuted in Life magazine in 1923. There were other kid cartoons, but Skippy broke ground by worrying, wondering and conniving like a fully realized human being.

"An image of undefinable charm," wrote cartoonist Jules Feiffer in the introduction to "Skippy and Percy Crosby" by Jerry Robinson. "Skippy was the first strip to fathom the wonder of a boy."

Skippy turned Percy into a one-man franchise. William Randolph Hearst signed Crosby to King Features Syndicate, bringing Skippy to millions of readers. Eventually, there was a radio show and a whole dime store's worth of Skippy products. Paramount Pictures paid $25,000 for the film rights to one of his novels and "Skippy," starring newcomer Jackie Cooper, earned raves and an Academy Award for its director. Crosby moved to McLean with his wife and children and bought a sprawling estate on 200 acres of land.

Around this time, a start-up company called Rosefield Packing Co. launched Skippy peanut butter. The company never paid a license fee to Crosby, although the name, the fence and the splattered lettering on the label so closely resembled the cartoon strip that a lawyer for Rosefield's successor company acknowledged in an internal memo that "it would appear that at various times in the past we did `plagiarize' in our labeling some of the Skippy concepts."

In 1933, Rosefield applied to the U.S. Patent and Trademark Office to register the name Skippy on peanut-butter products. Crosby challenged that application, arguing that it infringed on his own Skippy trademark. Rosefield dropped the matter but continued churning out Skippy peanut butter. For whatever reason, there is no record that Crosby ever filed suit to defend his trademark.

In 1945, Crosby's 20-year-old federal trademark of Skippy expired. Skippy Peanut Butter, at that point, was a nationally known brand, and Rosefield soon registered it successfully in dozens of states.

"Crosby waited too long," says Paul Kilmer, a trademark lawyer at Gadsby & Hannah who has studied the court record in the case. "Rosefield built up a business, Crosby didn't press his claims, and by the late 1940s he was out of luck."

By then, Crosby had more than peanut butter on his mind. A strident tone had been steadily creeping into his work as he crusaded against Prohibition, Al Capone and FDR, whom he denounced as a power-crazed autocrat. One year, he spent $32,000 on newspaper ads to broadcast his increasingly bitter tirades. The New Republic called him "the Mad Patriot."

His marriage, meanwhile, crumbled. After one argument, his wife left with the children and filed for divorce. Crosby would never lay eyes on his kids again.

Skippy, like his creator, began to brood, and in 1945 King Features dropped the strip. The Internal Revenue Service accused him of tax dodging, and he was forced to sell off his house. A desperate Crosby attempted suicide by slashing his wrists.

Doctors classified him as a "paranoid schizophrenic," and he was committed to the mental ward of Kings Park Veterans Hospital on Long Island. Few of his fellow patients ever knew that a former celebrity lived in their midst. Until his death in 1964, Crosby spun elaborate conspiracy theories about people who allegedly sought his ruin.

Tibbetts learned about her father's death by reading his obituary in the New York Times. She'd last seen him when she was 7, the day her mother packed up and left McLean. Her memories of the man are faint snippets from bygone holidays.

"He was like a kid," Tibbetts recalls. "At Christmastime, he had us call up the chimney to Santa Claus and he had the hired man sitting on the roof and he'd instructed him to yell `Ho ho ho' when we called up the chimney."

Tibbetts has a far stronger grasp on her ongoing legal skirmish. Speaking in urgent, stream-of-consciousness monologues, she recites every patent number, every court date, every lawyer who she says double-crossed her.

In 1968, Tibbetts became the administrator of her father's tiny estate. A few years later, she sought compensation from CPC International, which had merged with the company that purchased Rosefield in 1955 and which eventually spun off Bestfoods. In 1978, CPC wrote her a check for $25,000, while requiring her to release CPC from all past claims by the Crosby estate.

Tibbetts accepted the money but later contended she was duped. CPC representatives, she says, had promised to revive the Skippy character in its ads, and the $25,000, she alleges, was described as the first of many paydays.

She sued, alleging fraud, but a District Court judge in Virginia ruled against her in 1980, finding that the opportunity for a trademark suit had long since elapsed.

More litigation soon followed, and in 1986 a judge forbade Tibbetts from telling third parties that CPC lacked a trademark on the Skippy name for food products.

According to Bestfoods, which markets such mainstays as Hellmann's mayonnaise and Entenmann's cookies, the lengthy narrative at www.skippy.com violates the 1986 court order. "We've dealt gently with her in the past, even as she threatened us, defamed us, sought the attention of the press and shareholders," said Gale Griffin, a company spokeswoman. "She has been violating the injunction for years. But now she's gone too far."

Getting ready for her court date on Friday, Tibbetts doesn't like her odds. For starters, she doesn't have an attorney. She has spent nearly all her money and all her now-deceased husband's money pursuing this matter, hundreds of thousands of dollars.

Yet she laughs off the idea of dropping the case to dote on her grandchildren full time. It's not just the money and the mansion she remembers, though getting both back would be nice. There's a historical record to correct, and the memory of a forgotten man to burnish for a world that thinks Skippy is something you spread on a sandwich.

As her son, Waldo Tibbetts, puts it: "It's her life's work."