[1] The soundtrack was composed by Batman Begins collaborators Hans Zimmer and James Newton Howard and recorded in April.

[9] 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 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.

[10] 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".

The Digibook features several movie scenes, production details and a few words from Christopher Nolan on the collaboration with Hans Zimmer and James Newton Howard.

Filmtracks.com reviewer Christian Clemmensen found the track "Why so Serious" unlistenable and referred to it as "nine minutes of your life that you'll never get back", but praised the cue "Harvey Two-Face" which was composed by James Newton Howard.

Other complaints were about Batman's new heroic theme, featured most heavily in Like a Dog Chasing Cars, which Clemmensen considered "a murky blend of The Last Samurai, The Thin Red Line, The Da Vinci Code, and Crimson Tide".