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/Batman Batman discover each other's secret identities and agree to work together, even though they disagree with each other's methods of operating. The issue is a reimagining of "The Mightiest Team In the World", the tale from "Superman" #76 (May–June 1952) in which the two heroes discover each other's secret identities and team up for the first time. In "The Unexamined Life... " ("Annual" #2 (2008)), Superman loses his powers and takes on the identity of Supernova. The issue is a reimagining of "The Has-Been Superman" from "World's Finest Comics" #178 (September 1968) and "Superman's Perfect Crime" from "World's Finest Comics"