Ace Books is an American specialty publisher of science fiction and fantasy books. The company was founded in New York City in 1952 by Aaron A. Wyn and began as a genre publisher of mysteries and westerns. It soon branched out into other genres, publishing its first science fiction (SF) title in 1953.
In 1972, Ace was acquired by Grosset & Dunlap, and in 1982, Grosset & Dunlap was in turn acquired by G.P. Putnam's Sons. In 1996, Penguin Group (USA) acquired the Putnam Berkley Group, and has retained Ace as its SF imprint.