Nolan's inspiration for the film was the Joker's comic book debut in 1940, the 1988 graphic novel The Killing Joke, and the 1996 series The Long Halloween, which retold Two-Face's origin.
A inspiración de Nolan para o filme foi a banda deseñada do Joker de 1940, a novela gráfica de 1988 The Killing Joke e a serie de 1996 The Long Halloween, que conta a orixe de Two-Face.