Ace Books was started by A. A. Wyn, a publisher of pulps and hardcovers. The company is most famous for its line of Ace Doubles, and the Ace Science Fiction Specials. They are responsible for rescuing many good novels from pulp obscurity.
With the death of Mr. Wyn in 1967, the line foundered a bit, and was then sold to Charter Communications in 1970. Charter foundered and sold Ace to Grosset & Dunlap in 1972, and their other imprints in 1976 (such as Charter Books). Grosset & Dunlap also used the imprint Tempo, often combining Ace with these two, so there are Ace Charter books and Ace Tempo books, as well as Charter and Tempo books without the word Ace on them.
Grosset & Dunlap was purchased by the G. P. Putnam's Sons in 1982, and in 1996, Penguin Group (USA) bought the Putnam Berkley Group, and still own it today.
Throughout all of these ownership changes, Ace remained the primary science fiction imprint.
Among its many famous editors, Donald A. Wollheim went on the create DAW Books, Tom Doherty went on to create Tor Books, and James Baen, who had moved from Ace to Tor, went on to create Baen Books. Among its other successful editors was Terry Carr who worked at Ace from 1964 and 1971, and later again as a free-lancer. Carr is notable for editing the Ace Science Fiction Specials.