The Unknown is an anthology of fantasy fiction short stories edited by D. R. Bensen and illustrated by Edd Cartier, the second of a number of anthologies drawing their contents from the classic magazine Unknown of the 1930s-1940s. It was first published in paperback by Pyramid Books in April 1963. It was reprinted by the same publisher in October 1970, and by Jove/HBJ in August 1978 A companion anthology, The Unknown Five, was issued in 1964. The book collects eleven tales by various authors, together with a foreword by Isaac Asimov and an introduction by the editor.