Countdown, also known as Countdown to Final Crisis for its last 24 issues based on the cover, was a comic book limited series published by DC Comics. It debuted on May 9, 2007, directly following the conclusion of the last issue of 52. The series is written primarily by Paul Dini, along with a rotating team of writers and artists.Countdown consists of 51 issues, numbered in reverse and published weekly for one year. The series covers much of the fictional DC Universe, told in parallel narratives through the interconnecting stories of a cast of characters. It frequently crosses over with other DC titles. Unlike the 52 limited series of the previous year, Countdown is not depicted as taking place in "real time" but presumably operates on the same floating timeline as DC Comics stories in general. Source: Wikipedia (en)