The Killing Joke is a popular — and extremely divisive — Batman comic written by the legendary Alan Moore. It’s one of the most recognizable stories from the Caped Crusader’s backlog, illustrating an impressive staying power that very few stories experience. While a lot of the intention behind the story is left purposely ambiguous, fan theories have more-or-less cracked the context over the years. What fans get when they crack open the graphic novel is one of the more harrowing Batman tales featuring a truly haunting version of the Joker and more than a few twists one wouldn't find in most stories starring The Dark Knight.
Source：https://www.cbr.com/dcs-killing-joke-film-missed-the-point/
