Music of Halo 2

The music of Halo 2 is the musical score to Halo 2.

Development
One of the first tracks composed for Halo 2 was The Last Spartan, which was the backing track for the 2002 Halo 2 announcement trailer. The Last Spartan is representative of many compositions in Halo 2, where composers Martin O'Donnell and Michael Salvatori introduced new motifs, whilst reusing and incorporating musical themes from Halo: Combat Evolved. In the case of The Last Spartan, the track begins with its own motif before ending with Cloistered Expectancy, the Halo 2 rendition of the Gregorian chant. Other examples include Impend, which opens with the ending of Brothers in Arms, and Heretic, Hero, which opens with its own melody before incorporating the main melody of A Walk in the Woods in its second half. Other than the Gregorian chant, only two tracks in Halo 2 were outright arrangements of tracks from Halo: Combat Evolved, including Remembrance (arrangement of The Maw) and Cold Blue Light (arrangement of the fourth section of Opening Suite).

The Last Spartan also demonstrated the reuse of motifs introduced in Halo 2, with its motif incorporated into two other tracks that were composed in the early stages of the development. Skyline, likely written early due to its inclusion in the Halo 2 E3 demo, incorporated the main motif of The Last Spartan. Similarly, Earth City, another track composed for the demo and later featured prominently at multiple points in the game, incorporated the main motif of The Last Spartan as well as the Gregorian chant from the Halo Theme.

Halo Trilogy: The Complete Original Soundtracks
In 2008, after the release of Halo 3, a box set was released, featuring the Halo: Original Soundtrack, the Halo 2: Original Soundtrack, Volume 2, and the Halo 3: Original Soundtrack.