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The Time-Life numbering scheme is SUD-xx for "Superhits" and AM1-xx for "AM Gold". Note that for the discs "1971", "1972" and "Early '70s Classics" (and possibly others), the first pressings of the "AM Gold" versions were identical to their "Superhits" counterparts; later pressings swapped out one or two tracks and are identified with a reissue ...
Time Life added music in 1967, selling box sets and collections through Time–Life Records. During the 1960s and 1970s, the collections released by Time–Life Records catered to a conservative adult audience, with genres including classical, jazz, swing and orchestral music; and the music of operas and Broadway theatre.