Halo: Reach Original Soundtrack
From Halopedia, the Halo wiki
The Halo: Reach Original Soundtrack was released in stores September 28, 2010, and was distributed via iTunes and Sumthing Digital on September 14. There are a total of 20 tracks in the two-disk set comprising a total of 67 minutes worth of music.
The Halo: Reach Soundtrack marks the final time composers Martin O'Donnell and Michael Salvatori collaborate and compose original music for a Halo game. In a press release, Martin O'Donnell referred to the soundtrack as "...the culmination of our efforts".