Ace Books began publishing genre fiction in 1952. Initially these were mostly in the attractive tête-bêche format, but they also published a few single volumes, in the early years, and that number grew until the doubles stopped appearing in about 1978. The tête-bêche format was discarded in 1973, but future double novels were continued for a while, This list covers the non-double novels, for both the letter-series and numeric-series books. For the Ace Double volumes, see Ace Doubles.