Batman The Killing Joke tells the origin of Joker, establishing the fact that the only person who perfectly understands the Dark Knight is none other than the Clown Prince of Crime, and vice-versa. They coexist in Gotham City because they are in fact a single entity who split up, two sides of a coin, after becoming victims of one bad day. In this Alan Moore Batman, the Joker proves his point that a single tragic day is all anyone really needs to become mad. Batman The Killing Joke is thin because it strikes you with a remarkably sharp story. The panel transitions, colors, speech bubbles are just plain perfect with the action, emotions and character examinations. Both Batman crazy lovers and comic enthusiasts will love this book.