30 Iconic Comics All Batman Fans Must Own

27. Batman: The Killing Joke

The Killing Joke is another Joker origin story, but this one focuses on the Clown Prince of Crime wanting to prove that, given the right push, anybody can fall into the clutches of madness, prompting Batman into action.

In this story, Joker focuses his attentions on Jim Gordon, but finds that truly sane and good people can't be manipulated into going insane - though that's not to say Gordon's experiences didn't traumatise him massively.