Batman #570 1999

Batman #570, published by DC in October 1999, features "The Code, Part 1: Breakin' the Law" during the "No Man's Land" event. Harley Quinn returns, attempting to influence Joker's expanding territory using a new philosophy. Joker, in turn, makes a power play that threatens to reshape Gotham. This issue is highly notable to collectors as it marks Harley Quinn's first appearance in an ongoing mainstream DC comic book title, and is considered her second overall appearance in the main DC universe. It also introduces the character Josh.