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
Superman (Earth-One) the first time Superboy was referenced in a Superman story. The Earth-One Superman's first appearance (in a flash-forward) in a Superboy story was in "Superboy" (volume 1) #1 (March–April 1949). This version of Superman remained in publication through 1986. After the 1985-86 miniseries "Crisis on Infinite Earths", the Earth-One Superman was written out of continuity with the 1986 John Byrne miniseries "The Man of Steel". However, the Earth-One Superman was given a send-off in the final, noncanonical-to-Earth-One "imaginary" story "Whatever Happened to the Man of Tomorrow?" in "Superman" (volume 1) #423 (September 1986) and "Action Comics" #583 (September 1986). "For