Along with Frank Miller's The Dark Knight Returns and Art Spiegelman's Maus, Moore's Watchmen (illustrated by Dave Gibbons) is credited with having brought an air of respectability to comics in the 1980s through its plot, which many considered mature and thoughtful, some critics heralding it the greatest comic book ever produced upon release.
He has written a number of other famous comics, including From Hell, V for Vendetta, The League of Extraordinary Gentlemen, and the one-shot Batman: The Killing Joke.