Ralph Mayo was the art director of AC Comics in the 1940s. He drew 'Black Terror and Tim' for America's Best Comics, Black Terror and Exciting Comics. He also pencilled some 'Miss Masque' splash pages. In the 1950s he drew 'Jann of the Jungle' for Marvel, 'Camilla' for Fiction House and crime stories for Lev Gleason and St. John. He was penciler and/or inker on Dell titles like 'Dragoon Wells Massacre', 'Jungle Jim', 'Lassie', 'Quentin Durward' and 'Roy Rogers'.