Jerry Siegel, whose teen-age yearning for girls gave the world Superman, died in Los Angeles on Sunday. He was 81 but was remembered less as the Cleveland visionary who dreamed up the greatest superhero of all time than as the naive young man who sold the rights to a billion-dollar cultural and commercial juggernaut for $130.

It was Mr. Siegel's partner, Joe Shuster, who eventually gave Superman his familiar skin-tight costume and accompanying cape, but it was Mr. Siegel who had imagined Superman whole, from his birth on the doomed planet Krypton and his rocket arrival on Earth to his superhuman powers and his mild-mannered alter ego, Clark Kent.

The vision, as he later told it, came to him in a jumble all at once, during a sleepless summer night in Cleveland in 1934 after his graduation from Glenville High School, where he and Mr. Shuster had already teamed up to produce a stream of comic strip characters, including an earlier Superman, whom Mr. Siegel had imagined as a bald mad scientist.

But for all of the instant-imagined detail of the second Superman's extraterrestrial origins, his upbringing by doting foster parents and his decision to dedicate his awesome powers "to assist humanity," Mr. Siegal made no secret that the focus of his creative vision, the real creature of his dreams, was Lois Lane, Kent's fellow reporter on The Daily Planet.

She was the woman who would yearn for Superman even as she shunned Kent, not knowing that beneath that mild-mannered exterior was in fact the very man of steel, not to mention the longing heart of Jerry Siegel.

Even discussing Superman's origins 40 years later, Mr. Siegel, who said he had thought of becoming a reporter, seemed still to feel the stings he had suffered as a scrawny, bespectacled high school student:

"I had crushes on several attractive girls who either didn't know I existed or didn't care I existed," he said. "It occurred to me: what if I had something going for me, like jumping over buildings or throwing cars around or something like that?"

Even after Mr. Shuster had rendered Mr. Siegel's fantasy in ink, it took the partners several years to find a publisher willing to accept their creation.

And when they did, in New York, where they had been hired to produce other comic book characters, their dream of cashing in was quickly shattered.

In March 1938, in exchange for $130 in cash, they signed away all rights to Superman to DC Comics, the company that brought Superman to commercial life that June.

When the character proved an immediate sensation and the partners sought a share of the profits, they were dismissed and lived the rest of their lives near the poverty line. After a series of lawsuits to recover their creative property failed, Mr. Shuster was eventually reduced to becoming a messenger in Manhattan and Mr. Siegel worked as a clerk typist in Los Angeles for $7,000 a year.

In 1978, after the first Superman movie made more than $80 million, DC, which over the years has received more than $250 million of the more than $1 billion that Superman has earned from movies, television and an incredible array of commercial products, bowed to public opinion, restored their bylines and gave each man a $20,000-a-year annuity, later raised to $30,000.

In their final years, the two men lived within a few blocks of each other in Los Angeles, where Mr. Shuster, blind in the last years of his life, died in 1992.

Mr. Siegel may have been the man who created Superman, but his failure to safeguard his rights soured him on the man from another planet.

"I can't stand to look at a Superman comic book," he said in 1975. "It makes my physically ill. I love Superman, and yet to me he has become an alien thing."

He is survived by his wife, Joanne, their daughter, Laura Carter Larson of Los Angeles; a son, Michael, by a previous marriage, and two grandchildren.

Jerome Siegel