John Oliver Killens, 71, a teacher, novelist, playwright and essayist who was a founder and chairman of the Harlem Writers Guild and vice president of the Black Academy of Arts and Letters, died of cancer Oct. 27 in the Metropolitan Jewish Geriatric Center in Brooklyn, N.Y.

Whether as teacher or novelist or essayist, Mr. Killens strove in all his work to distill and express the black experience in this country. In doing so he reached an audience that transcended boundaries of race or color to express common denominators in human nature.

"I think I'm a man who has made a helluva lot of mistakes in my life, but I've always been in there pitching," he once said. "I have always worked for black liberation, but I've changed my mind a million times about how . . . to achieve it."

In the 1970s, Mr. Killens was a writer-in-residence at Howard University's Institute for the Arts and Humanities. He also had taught at such institutions as Fisk and Columbia universities and the New School for Social Research in New York City.

He contributed articles to Ebony, Black World, The Black Aesthetic and African Forum magazines. He was cowriter of the screenplay for the 1960 film "Odds Against Tomorrow" and he wrote the screenplay for the 1969 film "Slaves." His writing has been translated into more than a dozen languages.

Mr. Killens was the author of the 1971 volume of essays, "Black Man's Burden," published by Simon & Schuster. He was author of the play "Lower Than Angels," which was produced in New York in 1965, and was coauthor of the play "Ballad of the Winter Soldier," which played both here and in New York in 1964.

But he is probably best known for his novels, especially his first two, "Youngblood," published by Dial in 1954, and "And Then We Heard the Thunder," published by Knopf in 1962.

"Youngblood" told the story of blacks growing up and striving to improve their lot in a town much like Mr. Killens' native Macon, Ga. His second novel, again partly autobiographical, told the story of a black student who drops out of law school at the outbreak of World War II and becomes an officer in an all-black amphibious unit. The story follows the young officer as he finds out that while he is fighting fascism and racism overseas, similar enemies lurk near home. The book was nominated for a Pulitzer Prize.

His last book, now scheduled for publication, was "The Great Black Russian: The Life and Times of Alexander Pushkin," which is a biography of the 19th-Century Russian writer who had African blood.

Mr. Killens was a graduate of Howard University, and he studied law at the old Terrel Law School and creative writing at Columbia University. He was a clerk with the National Labor Relations Board here from 1936 to 1946. During World War II, he served with Army amphibious units in the Pacific, and began to regard writing as his calling.

He once told a reporter that it was during the war that he abandoned his plans and his family's dreams that he become a physician or lawyer. By the end of the war, "I knew that writing was the thing for me. It would be my raison d'etre, and nothing else would matter . . . . I found out, of course, that writing was the damnedest, hardest, and loneliest buck a man could make, especially if that man was black."

Survivors include his wife, Grace, a son, a daughter, his mother and two brothers.