began leading up to the new Crisis with a one-shot issue Countdown to Infinite Crisis, followed by four six-issue limited series that tied into and culminated in Infinite Crisis. Once the Crisis was completed, DC used the One Year Later event to move the narratives of most of its DC Universe series forward by one year. The weekly series 52 began publication in May 2006, and depicts some of the events which occurred between Infinite Crisis and One Year Later. In June 2008, a third series, Final Crisis, set immediately following the conclusion of the 51-issue Countdown to Final Crisis, began. Publication history Lead-upsInfinite Crisis was announced in March 2005. The event was kicked off with the release of Countdown to Infinite Crisis. Countdown to Infinite Crisis was followed by four six-issue limited series: The OMAC Project, Rann–Thanagar War, Day of Vengeance, and Villains United, as well as a four-part limited series DC Special: The Return of Donna Troy. These first four limited series each had a special tie-in issue, released at monthly intervals during the Infinite Crisis event. Tie-ins As with many large-scale comic crossovers, Infinite Crisis featured a large number of tie-ins. Before the event was announced, books such as Adam Strange and Identity Crisis were being described as part of bigger plans. After Countdown, several books were identified as tie-ins to the four mini-series. Thus, although Infinite Crisis itself is only seven issues long, its plot elements appeared in dozens of publications. Some of these books were of direct and major importance, such as the Superman "Sacrifice" and JLA "Crisis of Conscience" storylines, the latter of which ended with the Justice League's lunar Watchtower being destroyed, leading directly into Infinite Crisis #1. Countdown to Infinite Crisis #1 Infinite Crisis #1–7 Infinite Crisis Secret Files and Origins 2006 Day of Vengeance #1–6, Infinite Crisis Special #1 The OMAC Project #1–6, Infinite Crisis Special #1 Rann–Thanagar War #1–6, Infinite Crisis Special #1 Rann-Thanagar Holy War #1–8 Villains United #1–6, Infinite Crisis Special #1 Action Comics #826, 829–831, 836 Adam Strange Special #1 Adventures of Superman #639, 642–643, 645, 648–649 Aquaman #35, 37 Batman #635–641, 645–650, Annual #25 Batman: Gotham Knights #66 Birds of Prey #83, 87–90 Breach #7 Blood of the Demon #6–7 Catwoman #46–49 DC Special: The Return of Donna Troy #1–4 Firestorm #17–22 The Flash #225 Gotham Central #37 Green Arrow #52-59 Green Lantern #7 Hawkman #46–49,