25. "Knockin' on Heaven's Door" (1973)
Always a fan of westerns (and outlaws of every stripe), Dylan wrote a handful of songs for Sam Peckinpah's 1973 film, Pat Garrett & Billy the Kid. Jerry Fielding, a composer brought in to help Dylan with the music, described his reaction to hearing this heartbreaking sketch of a dying lawman: "It was shit. That was the end for me." Dylan, of course, had the last laugh. "Knockin' on Heaven's Door" became a Number 12 hit and one of his most-covered songs. Musically, it's also one of his simplest compositions – if you can play four easy chords and remember seven lines, you've got it down – which may be why, when a guest star shows up for the encore at a Dylan show, this is often the song that gets performed.