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 tried other genres. ace published its first science fiction (sf) book in 1953. this was successful, and ace soon published more science fiction books than both mysteries and westerns. ace became known for the "tête-bêche" publishing format used for many of its early books. but, it did not invent the format. most of the early books were published in this "ace double" format, and ace continued to publish books in several genres, in "tête-bêche" format, until 1973.