He is the world's most famous personality, better known in this country than anyone living or dead, real or fictional. Market researchers say his 97 percent recognition rate in the U.S. edges even Santa Claus.

He is the one — and for now only — Mickey Mouse.

As Mickey turns 80 this fall, the most beloved rodent in show business is widely regarded as a national treasure. But he is owned lock, stock and trademark ears by the corporate heirs of his genius creator, Walt Disney.

Brand experts reckon his value to today's Walt Disney Co. empire at more than $3 billion. Acts of Congress have extended Mickey's copyright so long that they provoked a Supreme Court challenge, making Mickey the ultimate symbol of intellectual property.

All signs pointed to a Hollywood ending, with Disney and Mickey Mouse living happily ever after — at least until a grumpy former employee looked closely at fine print long forgotten in company archives.

Film credits from the 1920s revealed imprecision in copyright claims that some experts say could invalidate Disney's long-held copyright, although a Disney lawyer dismissed that idea as "frivolous."

Although studio executives are not yet hurling themselves from the parapets of Sleeping Beauty's castle, the discovery raises an intriguing question: Is it possible that Mickey Mouse now belongs to the world — and that his likeness is usable by anybody for anything?

For the record, any knock-offs would have to make clear that they do not come from Disney or risk violating the separate laws that protect trademarks. And the potentially free Mickey is not the most current or familiar version of the famous mouse.

Copyright questions apply to an older incarnation, a rendition of Mickey still recognizable but slightly different. Original Mickey, the star of the first synchronized sound cartoon "Steamboat Willie," and other early classics, had longer arms, smaller ears and a more pointy nose.

The notion that any Mickey Mouse might be free of copyright restrictions is about as welcome in the Magic Kingdom as an old hag with a poisoned apple. Yet elsewhere, especially in academia, the idea has surprising support.

"That 'Steamboat Willie' is in the public domain is easy. That's a foregone conclusion," said copyright scholar Peter Jaszi of American University's Washington College of Law.

WISH UPON A STAR

The issue has been chewed over by law students as class projects and debated by professors. It produced one little-noticed law review article: A 23-page essay in a 2003 University of Virginia legal journal argued that "there are no grounds in copyright law for protecting" the Mickey of those early films.

Roger Schechter, a George Washington University expert on copyright, called the article's argument "a plausible, solid, careful case." By contrast, a Disney lawyer once threatened the author with legal action for "slander of title" under California law. No suit was filed.

The story begins once upon a time, when a longtime Disney devotee dared awake the dragon in the Disney company's legal department.

Gregory S. Brown, 51, a former Disney researcher who has lived in the same one-bedroom Hollywood apartment for two decades, seems an unlikely giant-killer. Thin, pale and bespectacled, he looks the part of an obsessive archivist. He has worked little since a heart attack in 1998, getting by mostly on disability payments.

As a child, Brown was intrigued by a book on the hard slogging by Walt Disney and his brother Roy to establish themselves in the early days of film and animation. That launched a lifelong fascination with the business side of the Disney empire.

While in high school, Brown visited Disney offices to research a term paper and ended up getting hired as an assistant to Disney archivist David R. Smith in 1974. Brown helped catalog correspondence between the Disney brothers and had access to other internal records.

Brown was struck by the Disneys' early disorganization. It took years, for example, for the brothers to decide whether their company should be a corporation, a proprietorship or a partnership.

GHOST OF A CHANCE

Brown moved on from Disney to UCLA, the American Film Institute and a brief producing career, and then he teamed with a friend in a 1980s takeover bid for Harvey Productions — home of Casper the Friendly Ghost.

Conducting a "due diligence" assessment of Harvey's assets — making sure that no legal or financial problems could haunt the purchase — Brown found a stinker.

Harvey sued Columbia Pictures in 1984 over the movie "Ghostbusters," complaining that the cartoon ghost in the logo of Bill Murray's crew looks an awful lot like Casper's sidekick, Fatso. Columbia Pictures convinced a judge that a lapsed copyright had dumped Fatso into the public domain, ending the case.

Brown also discovered that Harvey had failed to renew other copyrights covering the company's ghosts. Casper was public property, too.

Now armed with knowledge about the frequency and implications of copyright confusion, Brown launched a business venture exploiting some of that murkiness. He would market re-created animation cels from a 1933 Mickey Mouse short called "The Mad Doctor." Brown had discovered that the Disneys failed to renew copyright claims on that film.

But the Disney company sued so quickly that Brown never sold a cel. While "The Mad Doctor" was indeed out of copyright, that long-ago oversight had not freed Mickey, whose ostensible copyright protection predated the short.

Brown lost. Worse, he was clobbered with a $500,000 judgment.

OOPS OF OLDEN DAYS

In the waning days of his case, Brown returned to the arguments of Disney lawyers who wrote that Mickey Mouse had been created by Walt Disney Co. in 1928. The former archivist knew that the company didn't exist then. He wondered: Whose name is on the original copyright?

Brown was one of the few who knew that odds of a mistake were high. "Everybody screwed up copyright in the '20s, '30s and '40s," said Schechter, the author of several books on copyright law. "Under the 1909 Act, courts were really insistent on formalities."

Brown went searching for flawed formalities — and found one. It was on the title card at the beginning of a "Steamboat Willie" cartoon that had just been rereleased on a 1993 LaserDisc honoring Mickey's 65th birthday. It said in full:

"Disney Cartoons

Present

A Mickey Mouse

Sound Cartoon

Steamboat Willie

A Walt Disney Comic

By Ub Iwerks

Recorded by Cinephone Powers System

Copyright MCMXXIX."

For Brown, it was as if the glass slipper fit him perfectly. The key was location of the word "copyright" in relation to the name "Walt Disney." There were two other names listed in between — Cinephone and Disney's top studio artist, Ub Iwerks. Arguably, any of the three could have claimed ownership, thereby nullifying anyone's claim under arcane rules of the Copyright Act of 1909.

Brown leapt on the ambiguity, asking the court to reconsider its ruling against him on grounds that Mickey Mouse was out of copyright. But he was too late. Without ruling on the merits of Brown's arguments, the judge tossed it aside as untimely.

Arizona State University professor Dennis Karjala, a Brown acquaintance, suggested that one of his law school students look into the claim as a class project. Lauren Vanpelt took up the challenge and produced a paper agreeing with Brown.

She posted her project on the Internet in 1999.

CLAP IF YOU BELIEVE

Across the continent, a Georgetown University law student stumbled on Vanpelt's paper more than a year later. "I just came across it," Douglas Hedenkamp said. "I was intrigued."

Today, title-card claims are no longer required. But when courts rule on historical copyright issues, they follow the laws in place at the time — in this case, Hedenkamp says, the 1909 law requiring that the word copyright or its symbol be "accompanied by the name of the copyright proprietor" — a rule scholars said means in the immediate proximity.

Hedenkamp finally wrote to Disney's in-house lawyers, an attempt to satisfy his curiosity. Had he missed something? Or was there really a problem with Mickey's copyright?

Disney legal advisers were not amused. General counsel Louis Meisinger wrote back that it would be "inconceivable that any modern court would find any confusion about the identity of the proprietor of Mickey Mouse cartoons."

Nonetheless, Hedenkamp spelled out his arguments in the Virginia Sports and Entertainment Law Journal, a publication of the University of Virginia's law school. It attracted little attention off-campus.

Hedenkamp never heard from Disney again. Now 32, he works at an Irvine, Calif., firm handling commercial law.

He describes himself as a "huge fan" of Disney. He also says that because Disney has taken advantage of so many characters created by others, it is only fair that artists get to borrow from Disney.

"Other people should get to put their spin on those old characters," Hedenkamp said.

Roy Disney said he had never heard the theory about problems with the title cards. Nor was he surprised.

During those early years, he said, "Nobody knew what they were doing."

Meisinger, the former general counsel, is now a Los Angeles County judge. Asked about the Hedenkamp article during a visit to his chambers, Meisinger gave an instant nod of recognition but ignored an invitation to take up the argument again.

"Everything has to fall into the public domain sometime," he said, then headed back to court.