Superman: Whatever Happened to the Man of Tomorrow? reference to one of the nicknames of Superman as the "Man of Tomorrow", and was later again used in the title of another Superman . The comic book, "Action Comics" #1, published in April 1938 by "National Allied Publications" (later renamed DC Comics), marked the first publication of the character of Superman created by Jerry Siegel and Joe Shuster. The comic quickly became a success, and its editor soon realized that it was because of the popularity of the character. In an unprecedented move at the time, National Allied Publications introduced a second comic book, "Superman", exclusively featuring the popular
Adventure Comics adventure series. In issue #12 when the series was titled "New Adventure Comics", Joe Shuster and Jerry Siegel introduced the first version of the character Jor-L as a science fiction detective in the far future; the character would eventually become the alien father of Superman, although the first Superman story, in "Action Comics" #1, would not appear until more than a year after Jor-L's first appearance. The series' focus gradually shifted to superhero stories starting with the debut of the Sandman in issue #40. Other superheroes who appeared in the early days of "Adventure" included Hourman (from #48 to #83);