Alternative versions of Superman establish a new continuity for DC, affecting not only Superman, but all of the DC Comics characters. The versions of Superman from this time period are traditionally divided into three main periods. The first version of Superman began being published by DC Comics in 1938 appearing in "Action Comics" #1. To explain discrepancies in the aging of Superman across several decades, his earliest stories were retroactively portrayed as having taken place on an alternative world called Earth-Two. These stories take place from 1938 until the late 1950s, although the exact dividing line is unclear and some stories happened identically to
John Byrne (comics) (July–Sept. 1986), the first issue of which was marketed with two different covers illustrated by Byrne, the first use of variant covers by the American comics industry. Byrne penciled the six-issue DC Universe crossover miniseries "Legends" (Nov. 1986 – May 1987) during this time. He wrote and drew two monthly Superman titles with the hero's present-day adventures: a new "Superman" title beginning with issue #1 (January 1987) and "Action Comics", in which, beginning with issue #584, Superman teamed up with other DC characters. The original "Superman" book was renamed "The Adventures of Superman" starting with issue #424 and was initially