Zero Hour: Crisis in Time - Background

Background

Zero Hour: Crisis in Time was intended by DC as a belated follow-up to their landmark limited series Crisis on Infinite Earths, and was indeed subtitled "(A) Crisis in Time". It promised to do for the inconsistent future timelines of the DC Universe what Crisis had done for its parallel worlds: unify them into a new one.

This event served as an opportunity to reconcile some of the problems left unaddressed by Crisis and other problems that had been unintentionally caused by it. In particular, the revised characters of the post-Crisis universe had been rolled out gradually, with DC continuing to feature the old versions until the new versions were launched, some of them a year or several after the first wave of revised characters were published (i.e., The Man of Steel, Wonder Woman vol. 2, Batman: Year One). The character of Hawkman was one of the most problematic, since the revised version did not first appear until 1989. This raised the question of what version of Hawkman had been seen since 1986 (he had been retconned to be both the Golden Age Hawkman and a Thanagarian spy). The Legion of Super-Heroes faced similar problems with the eliminations of Superboy and Supergirl from DC continuity (Mon-El, a character with similar powers, had been recast as Valor to take Superboy's place as the Legion's inspiration and most powerful member). These and other retcons were not always well received by readers and often introduced new problems.

The Sandman: Worlds' End is loosely connected with Zero Hour, as can be seen from the Sandman annotations.