After spending six years in the Navy, Dave Cockrum began his career in comics at Warren Publishing. There, he did work for Warren's magazines, such as Creepy, Eerie and Vampirella. He then began inking Murphy Anderson's backgrounds on the 'Superboy' and 'Superman' comics for DC. Cockrum's first big work was the 'Legion of Superheroes' strip, which appeared as the backup feature of the 'Superboy' comic book.
Yesterday is the day before tomorrow (Eerie #39, 1972)
He then went to Marvel, where he helped revive the 'X-Men' comic in the 1970s. After two 'X-Men' books, Cockrum began his own 'The Futurians' series, at first for Marvel, but later for the independent Lodestone publishers. When Lodestone folded, he did several jobs for DC, Valiant, Defiant and Broadway, followed by Claypool Comics, for which he did 'Soulsearchers and Company'.
G.I. Joe Special Missions #22