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
Superman in film DVD/home video releases of "Superman", "Superman II", "Superman III", and "Superman IV". The set was valued at US$49.99 for the DVD release and US$29.99 for the VHS release, and received positive reviews. The four Christopher Reeve films were again released on November 28, 2006, in new DVD releases to coincide with "Superman Returns", also released in that year. "Superman" was released in a four-disc 'special edition' similar to "Superman II", which was released in a two-disc special edition. Both "Superman III" and "IV" were released in single disc 'deluxe editions', and all four releases were available together in "The Christopher