



As a writer, Gruenwald is best known for creating the Official Handbook of the Marvel Universe and his ten-year stint as the writer of Captain America during which he contributed several notable characters such as Crossbones, Diamondback and U.S. In 1982, Gruenwald, Steven Grant, and Bill Mantlo co-wrote Marvel Super Hero Contest of Champions, the first limited seriespublished by Marvel Comics.

During this period, he shared an office with writer/editor Denny O'Neil, whom Gruenwald considered a mentor. Hired initially as an assistant editor in January 1978, Gruenwald was promoted to full editorship by Marvel editor-in-chief Jim Shooter in 1982, putting Gruenwald in charge of The Avengers, Captain America, Iron Man, Thor, Spider Woman, and What If. In 1978 he was hired by Marvel Comics, where he remained for the rest of his career. Articles by Gruenwald include "The Martian Chronicles" (a history of the Martian Manhunter) in issue #13 and several articles on the history of the Justice League in issue #14. Before being hired by Marvel, he wrote text articles for DC Comics official fanzine, The Amazing World of DC Comics. Gruenwald got his start in comics fandom, publishing his own fanzine, Omniverse, which explored the concept of continuity.
