This comics digest retells the origin of the Challengers of the Unknown. It also includes stories reprinted from Adventure Comics #282 and # 419, Action Comics #276, Captain Marvel Adventures #50, DC Showcase #64 and Aquaman #42. Other heroes include the Legion of Superheroes, Superboy, Supergirl, Zatanna, Captain Marvel, the Spectre and Aquaman. The scripts are by Bob Rozakis, Otto Binder, Steve Skeates, Len Wein, Jerry Siegel, and Gardner Fox. The pencils are by George Tuska, George Papp, Jim Aparo, Dick Giordano, Jim Mooney, Pete Costanza, and Murphy Anderson. The front and back covers are by Keith Giffen.