With longtime songwriting partner Benny Andersson, Swedish singer-producer Björn Ulvaeus was the creative force behind the vocal group ABBA, which became one of the most successful pop groups in music history, selling over 370 million singles and albums worldwide. Ulvaeus and Andersson co-wrote the majority of the group's hits, including the chart-topping "Dancing Queen," "Waterloo," "Knowing Me, Knowing You," "SOS" and dozens of others, which were earmarked by the sparkling four-part harmonies of Ulvaeus and Andersson with singers Agnetha Fältskog Anni-Frid Lyngstad, whom were also their respective spouses, and a lush, dance-friendly production style that put them at the forefront of the international pop scene in the 1970s. ABBA soon became massively popular throughout Europe, Australia and Latin America, with America coming somewhat late to the party in the mid-1970s when the group reached its creative apex with the No. 1 sensation "Dancing Queen." However, personal turmoil between the two couples and declining stateside interest in all things disco-friendly led to their breakup in 1982. Ulvaeus and Andersson transitioned to the theatrical world, penning the U.K. hit musical "Chess" and co-producing the global smash "Mamma Mia!" which featured a number of their vintage hits. The band itself and their original singles also underwent a revival in the 1990s, thanks to films like "Muriel's Wedding" (1994) and covers by newer pop artists that sent their greatest hits collections back up the charts. Ulvaeus' central role in the mini-industry that sprung up around ABBA even years after its demise, made him one of the most successful songwriter-producers of the 20th century and beyond.