The best soundtracks are like movies for the ears, and <em>O Brother, Where Art Thou?</em> joins the likes of <em>Saturday Night Fever</em> and <em>The Harder They Come</em> as cinematic pinnacles of song. The music from the Coen brothers' Depression-era film taps into the source from which the purest strains of country, blues, bluegrass, folk, and gospel music flow.