Upon leaving Ace, he and his wife, Elsie Balter Wollheim, founded DAW Books, named for his initials. DAW can claim to be the first mass market specialist science fiction and fantasy fiction publishing house. DAW issued its first four titles in April 1972. Most of the writers whom he had developed at Ace went with him to DAW: Marion Zimmer Bradley, Andre Norton, Philip K. Dick, John Brunner, A. Bertram Chandler, Kenneth Bulmer, Gordon R. Dickson, A. E. van Vogt, and Jack Vance. In later years, when his distributor, New American Library, threatened to withhold Thomas Burnett Swann's Biblical fantasy "How Are the Mighty Fallen" (1974) because of its homosexual content, Wollheim fought vigorously against their decision and they relented.