Ace, along with Ballantine Books, was one of the leading science fiction publishers for its first ten years. The death of owner A. A. Wyn in 1967 created problems for the publisher. That was delayed several years by the Ace Science Fiction Specials series, prominent in science fiction awards and nominations for novels published from 1968 to 1970. Two leading editors, Donald A. Wollheim and Terry Carr, left in 1971, and in 1972 Ace was sold to Grosset &amp; Dunlap. Despite financial troubles, there were more successes, particularly with the third Ace Science Fiction Specials series, for which Carr came back as editor. Several sales of the company resulted in the company becoming part of Berkley Books. Ace later became an imprint of Penguin Group (USA).