An American author of horror, fantasy, science fiction, and Gothic romance, he is best known for such short story collections as The Horror from the Hills (1963) and The Rim of the Unknown (1972). He was a major contributor to the Cthulhu Mythos, a series of stories inspired by the work of H.P. Lovecraft.
He studied journalism at New York University. He published his first work, a poetry collection entitled A Man from Genoa, in 1926.
He suffered a dangerous attack of appendicitis that nearly killed him.
He was the son of a Manhattan dentist. He married Lyda Arco.
He and H.P. Lovecraft were close friends.