Hans Zimmer & James Newton Howard - The Dark Knight - Original Soundtrack (2 x LP Vinyl)

Zimmer originally said the main Batman theme was purposely introduced at the end of Batman Begins, and would be fleshed out in the sequel as the character develops. Zimmer and Howard both believed that creating a heroic theme that a viewer could hum would ignore the complexity and darkness of the character. The Batman theme (audible twice early in the film, once towards the end and a final time at the beginning of the end credits) creates what Zimmer described as a "red herring", a kind of musical foreshadowing, which was played by a cello.

The nine-minute suite for the Joker ("Why So Serious") was based around two notes played by electric cello, solo violin, guitars and a string section. Zimmer compared its style to the band Kraftwerk, who come from his native Germany, as well as his work with bands like The Damned. Throughout the piece, Zimmer used razor blades on string instruments to achieve the tortured, twisted sound to accompany the character on the screen. When Ledger died, Zimmer stated that he felt like scrapping his original material and composing a new theme, but decided that to do so would compromise the "evil [performance] projects". James Newton Howard composed the "elegant and beautiful" themes for Harvey Dent/Two-Face, to work as an aural contrast.