Much like Time-Life's other series chronicling popular music, volumes in the "Sounds of the Seventies" series covered a specific time period, including individual years in some volumes, and different parts of the decade (for instance, the early 1970s) in others; in addition, some volumes covered specific trends, such as music popular on album-oriented rock stations on the FM band. Each volume was issued on either compact disc, cassette or (with volumes issued prior to 1991) vinyl record. Individual volumes generally contained anywhere between 18 and 22 tracks, and represented the highlighted time period's most popular and noteworthy tracks. Also included was a booklet, containing liner notes written by some of the most respected historians of the genre, photographs of the artists, and information on the songs (writers, performers and peak position on Billboard magazine's Hot 100 chart).