"Book of Days" is a song by Irish musician Enya. The original version, included on her 1991 album Shepherd Moons, is sung in Irish Gaelic. The subsequent 1992 single version is bilingual, with new English lyrics; this version was recorded for Ron Howard's film Far and Away, and scenes from the film feature in the video. The bilingual English-Irish version replaced the original pure Gaelic version on subsequent pressings of Shepherd Moons from mid-1992 onwards, making the original recording relatively rare.