An American literary critic and biographer, he is best known for his profiles of such renowned authors as James Joyce, William Butler Yeats, and Oscar Wilde. His 1959 biography of James Joyce won the U.S. National Book Award for Nonfiction.
After graduating from Yale University and serving in the U.S. Navy during World War II, he studied literature at Trinity College, Dublin.
His history of William Butler Yeats became the definitive work on the author.
He was born in Highland Park, Michigan, to a Romanian immigrant father and a Russian immigrant mother. With his wife, Mary, he had two daughters and a son.
He won the Pulitzer Prize for his biography of the renowned novelist and playwright, Oscar Wilde.