The Unknown Five is an anthology of American fantasy fiction short stories edited by D. R. Bensen and illustrated by Edd Cartier, the fourth of a number of anthologies drawing their contents from the magazine Unknown of the 1930s-1940s. It was first published in paperback by Pyramid Books in January 1964. The cover title of this first edition was The Unknown 5; the numeral was spelled out on the title page and copyright statement. The book was reprinted by Jove/HBJ in October 1978. It has also been translated into German. It was a follow-up to a companion anthology, The Unknown, issued in 1963.