The soundtrack to Errol Morris' documentary The Thin Blue Line emphasizes story over music; the interviews which make up the majority of the film -- a crusading effort which led to the the release of its subject, Randall Adams, from a Texas prison -- are presented on record as they were on screen, with Glass' chamber orchestra music hovering in the background.
The result is a soundtrack which comes remarkably close to capturing the power of its source film; even without the moving images, this is a chilling document.