Fleetwood Mac is a rare rock band breed. Their musical triumphs are vast and storied, but their inner, soap opera relationships are just as legendary as their hit records.The band originally formed with Mick Fleetwood, John and Christine McVie in 1967. But it wasn't until 1975 that guitarist Lindsey Buckingham and then-girlfriend and musical partner, Stevie Nicks, joined and the best-known incarnation of the group came together.Looking to replace recently departed guitarist, Bob Welch, Fleetwood heard Buckingham-Nicks' self-titled album, and liked it enough to ask for an introduction to Buckingham. Fleetwood invited him to join Fleetwood Mac, but he would only agree on one condition: Nicks would become a member of the band as well.The new lineup included three members who could write songs and sing lead vocals - Christine McVie, Buckingham and Nicks, who all brought different sensibilities to their lyrics. The new band broke through with the self-titled album, Fleetwood Mac (1975), which sold over five million copies.