Even though it contains the classic rock standard "Knocking on Heaven's Door," PAT GARRETT & BILLY THE KID is one of Dylan's least-known albums. Recorded as the soundtrack to the surreal, somewhat violent Sam Peckinpah Western in which Dylan co-starred, the album consists mainly of reflective, rustic instrumentals. Of the two songs with vocals, "Billy" is a compelling outlaw narrative, complete with earnestly strummed acoustic guitars and Dylan's wheezing harmonica, while the epic, ominous "Knocking On Heaven's Door" is a rock masterpiece that evokes the wide-open space and desolation of the Old West. Though the remainder of the album is devoted to instrumentals, tracks like the delicate, wistful "River Theme" are impressive in their own understated way. Backed by Byrds' guitarist Roger McGuinn and an assortment of top-drawer West Coast session players, Dylan created a moody, mythic musical landscape on PAT GARRETT & BILLY THE KID. It was one of his last albums to capture the restless spirit and otherworldly feel of his classic sixties recordings.