an Entity references as follows:
Guitar Rock was a 27-volume series issued by Time-Life during the mid-1990s, spotlighting rock music—in particular, hard rock, classic and album-oriented rock of the 1960s through early 1990s. Much like Time-Life's other series chronicling popular music, volumes in the "Guitar Rock" series covered a specific time period, including two-year spans in some volumes and different parts of the decade (for instance, the early 1970s) in others. Each volume was issued on a compact disc or cassette. Except for two prototype volumes that preceded the series proper (where two CDs or two cassettes were issued in those particular volumes), individual volumes generally contained 18 tracks (this varied by one or two tracks per album), and represented the highlighted time period's most popular and notewort