Ralph Ellison, 80, author of "Invisible Man," widely considered the greatest American novel of the last 50 years, died yesterday at his home in New York. He had pancreatic cancer.

Published in 1952 after a labor of five years, "Invisible Man" takes its nameless black narrator on a brutal odyssey: from the "battle royal," where he is blindfolded and forced to fight other youths for the amusement of a white audience; to his expulsion from a Southern college for improper fraternizing with a white trustee; to his association with the mysterious and treacherous "Brotherhood"; and finally to a soul-destroying race riot in Harlem that literally sends him underground.

Poet Langston Hughes called the novel "a stunning blockbuster of a book that will floor and flabbergast some people, bedevil and intrigue others, and keep everybody reading right through to its explosive end."

That's pretty much the way it happened. "Invisible Man" spent 16 weeks on the bestseller list and won the National Book Award. In 1965, a Book Week poll of 200 critics, authors and editors judged it "the most distinguished single work" of the postwar period. By 1973, the book reportedly had sold 2.6 million copies.

Ellison published two nonfiction collections, "Shadow and Act" in 1964 and "Going to the Territory" in 1986. In both, he solidified his reputation as a man of letters and as a spokesman for moderation and the American melting pot.

During the late 1960s, the writer was attacked in some quarters for being neither angry nor militant enough. At Oberlin College in 1969 he was called an "Uncle Tom" and told, "Your book doesn't mean anything." To those and similar criticisms, the writer responded: "I'm not a separatist. The imagination is integrative. That's how you make the new -- by putting something else with what you've got. And I'm unashamedly an American integrationist."

It's a quality he shared with the narrator of his novel, who is not so much angry -- a quality that might have dated the book -- but ironic. The fictional character argues fiercely for a multi-hued diversity and variety.

"Why, if they follow this conformity business they'll end up by forcing me, an invisible man, to become white, which is not a color but the lack of one," the narrator says. "Must I strive toward colorlessness? But seriously, and without snobbery, think of what the world would lose if that should happen. America is woven of many strands; I would recognize them and let it remain so."

A measure of Ellison's influence on later generations of writers could be seen in 1990, when Charles Johnson won the National Book Award for his novel "Middle Passage."

The first black male to win since Ellison himself, Johnson paid the senior writer a lengthy tribute in his acceptance speech. "In the 1990s," he predicted, "we will see a black American fiction that will be Ellisonesque as we as a people move from narrow complaint to broad celebration."

Ellison, who was present, said he was "touched" but made clear that black writers shouldn't only be influenced by other black writers. "You don't write out of your skin, for God's sake," he said. "You write out of your imagination."

In 1981, Ellison wrote that he attempted in "Invisible Man" to fashion "a raft of hope, perception and entertainment that might help keep us afloat as we tried to negotiate the snags and whirlpools that mark our nation's vacillating course toward and away from the democratic ideal."

The novel, he added, initially was inspired "by nothing more substantial than a taunting, disembodied voice."

From the outset, the narrator recounts his story in an authoritative tone: "I am an invisible man. No, I am not a spook like those who haunted Edgar Allan Poe; nor am I one of your Hollywood-movie ectoplasms. I am a man of substance, of flesh and bone, fiber and liquids -- and I might even be said to possess a mind. I am invisible, understand, simply because people refuse to see me."

The novelist was born March 1, 1914, in Oklahoma City. His father was a construction foreman who died when young Ellison was 3; his mother a domestic worker, custodian and cook. In 1933, Ellison went to the Tuskegee Institute in Alabama, intending to be a composer (his instrument was the trumpet). A voracious reader, he discovered the power of literature through the study of T.S. Eliot's poem "The Waste Land." After three years, he ran out of money and ended up in New York. He worked at the Harlem YMCA, in factories and as a freelance photographer.

Lack of money played a major role in his decision to become a writer. "I've always read a lot, and I began to realize that I had a certain talent for it," he said in 1992. "It wasn't easy to be the kind of musician that I wanted to be; I didn't have enough money to enroll in Juilliard. So I stuck with what I had."

He was a charter member of the National Council on the Arts and Humanities and a member of the American Academy of Arts and Letters. He was the Schweitzer Professor of Humanities at New York University until 1980 and taught for brief periods at Bard College, the University of Chicago and Rutgers University.

One of the enduring mysteries about Ellison was why he never published a second novel. He began one in 1955 and published eight segments from 1960 to 1977 before deciding that any more excerpts would dilute the effect of the book as a whole. The book appears to be set in Washington and the South, and involves the black evangelist Hickman and his adopted son, Bliss, a boy preacher who passes for white and grows up to become the notorious racist Senator Sunraider. Ellison called the untitled work "a crazy book, and I won't pretend to understand what it's about."

By the early 1970s, he was reported to have more than a thousand pages completed. "It would be easy enough to write other fiction, to put out several books," the writer said in 1982. "You don't -- I don't -- write to satisfy other people. You do certain things and then you do other things, and you don't always publish what you write."

Survivors include his wife of 47 years, the former Fanny McConnell, of New York; and a brother, Herbert, of Los Angeles.