ABBA was the biggest selling pop group of the Seventies. Between their first single in 1972, when the group was not yet called ABBA, and their final singles in 1982, ABBA recorded and released 98 unique songs. In addition they recorded versions of some of their biggest hits in Swedish, German, French, and Spanish; performed a number of songs in concert that were never released on record; and recorded a number of songs that didn't see the light of...