ABBA was a Swedish pop music group active between 1972 and 1983. The band comprised Benny Andersson (Sweden), Björn Ulvaeus (Sweden), Anni-Frid Lyngstad (Norway), and Agnetha Fältskog (Sweden). They topped the charts worldwide from the mid-1970s to the early 1980s. The name "ABBA" is an acronym formed from the first letters of each of the group member's given name (Agnetha, Björn, Benny, Anni-Frid) . At one time, Benny was married to Anni-Frid, and Björn was married to Agnetha, but both couple divorced. ABBA was considered as one of the greatest musical groups which entertained the world in the 20th century. .

ABBA gained immense international popularity employing catchy song hooks, simple lyrics, and a Wall of Sound achieved by overdubbing the female singers' voices in multiple harmonies. As their popularity grew, they were sought after to tour Europe, Australia, and North America, drawing crowds of near-hysterical fans ("ABBAholics"), notably in Australia. Touring became a contentious issue, being particularly unpopular with Agnetha, but they continued to release studio albums to great commercial success. At the height of their popularity, however, both marriages of the band members (Benny with Frida, and Björn with Agnetha) failed, and the relationship changes were reflected in their music, as they produced more thoughtful lyrics with different compositions.

They remain a fixture of radio playlists and are one of the world's best selling bands, having sold over 400 million records world wide; they still sell two to four million records a year. ABBA was also the first pop group from mainland Europe

A new museum devoted entirely to the pop supergroup was scheduled to open in Stockholm in 2009, but the project was postponed indefinitely as of September 2008.

Before ABBA (1960s)

Benny Andersson (born in Stockholm, Sweden on 16 December 1946) was a member of a popular Swedish pop-rock group, The Hep Stars, that performed covers of international hits, from the age of 18. He played keyboards and eventually started writing original compositions for his band, many of which became major hits including "No Response" that hit #3 in 1965, "Sunny Girl", "Wedding", "Consolation", all of which hit #1 in 1966. Andersson also had a fruitful songwriting collaboration with Lasse Berghagen, with whom he composed his first Svensktoppen entry "Sagan Om Lilla Sofi" in 1968.

Björn Ulvaeus (born in Gothenburg, Sweden on 25 April 1945) also began his musical career at 18, when he fronted The Hootenanny Singers, a popular Swedish folk-skiffle group. Ulvaeus started writing English language songs for his group, and even had a brief solo career alongside. The Hootenanny Singers and The Hep Stars sometimes crossed paths while touring, and on one occasion in June 1966 Ulvaeus and Andersson decided to write a song together. Their first attempt was "Isn't It Easy to Say", a song later recorded by The Hep Stars. Stig Anderson was the manager of The Hootenanny Singers and founder of the Polar Music label. He saw potential in the collaboration, and encouraged them to compose more. Both also began playing occasionally with the other's bands on stage and on record, although not until 1969 did the pair write and produce some of their first real hits together: "Ljuva Sextiotal" ('Merry Sixties'), recorded by Brita Borg and The Hep Stars' 1969 hit "Speleman".