CRISIS ON INFINITE EARTHS was a 1985-86 crossover event storyline consisting of a core mini-series of the same name and multiple tie-in issues throughout DC's titles of that time period. It is the first of DC's 'crisis' events, which typically involve the Multiverse and an elevated threat to its existence. The first large-scale reboot of a major publisher (though not the first large-scale crossover event), CRISIS did away with the DC Multi-verse and replaced it with a single Earth. As you can imagine this necessitated a high casualty rate among DC's roster of superheroes, including pretty much the whole Golden Age dramatis personae. The deaths of Supergirl and Barry Allen are key deaths in the mini-series. The iconic cover to issue #7 with an emotional Superman holding the lifeless body of Supergirl is often the target of homage. CRISIS was followed by INFINITE CRISIS in 2005 and FINAL CRISIS in 2008, forming what is known today as the Crisis Trilogy. CRISIS is important as the precedent of a comic book company stirring their decades of publishing history in a large-scale event to appeal to long-time readers and simultaneously attract new readers as well as a company using their alternate universes as overarching characters themselves in metatextual context. Now, when analyzing the history and origin of any DC character, the discussion is often qualified with either a 'pre-Crisis' or 'post-Crisis' descriptor.
