Swedish singer Agnetha Fältskog shared lead vocal duties as part of ABBA, one of the most successful pop groups in music history, with over 370 million singles and albums sold worldwide. She was the primary vocalist on several of the group's biggest hits, including "SOS" and "Take a Chance on Me," while also sharing lead vocals with Agnetha Fältskog on "Waterloo," "Dancing Queen," "The Name of the Game" and contributing to ABBA's trademark four-part harmony with her husband, Björn Ulvaeus, and his songwriting partner, Benny Andersson. For much of the 1970s, ABBA was massively popular throughout Europe, Australia and Latin America, with the United States coming somewhat late to the party in the latter half of the decade when the group reached its apex with the No. 1 sensation "Dancing Queen." Personal turmoil between the two couples led to ABBA's breakup in 1982, after which Fältskog enjoyed solo stardom in Europe, though with only minor returns in America, before beginning a self-imposed hiatus in 1988. After enduring several problematic relationships in the 1990s, Fältskog returned to performing with <i>My Colouring Book</i> (2004), which charted highly throughout Europe. She soon returned to the public eye via reunions with her former group mates while continuing to mine hit singles on the Continent throughout the 2000s. Though her musical career contained many dramatic ups and downs, Agnetha Fältskog's efforts with ABBA minted her as one of the reigning queens of '70s pop as well as a vital performer in her own right.