The Who are an English rock band that formed in 1964. Their best known line-up consisted of lead singer Roger Daltrey, guitarist Pete Townshend, bassist John Entwistle and drummer Keith Moon. For much of their career they have been regarded as one of the three most important British rock acts along with the Beatles and the Rolling Stones and one of the world's best-selling bands of all time, having sold more than 100 million records.

The Who developed from an earlier group, the Detours, before stabilising around a line-up of Daltrey, Townshend, Entwistle and Moon. After releasing a single as the High Numbers, the group established themselves as part of the mod movement and featured auto-destructive art by destroying guitars and drums on stage. They achieved recognition in the UK after their first single as the Who, "I Can't Explain", reached the top ten. A string of successful singles followed, including "My Generation", "Substitute" and "Happy Jack". Although initially regarded as a singles act, they also found success with the albums My Generation and A Quick One. In 1967, they achieved success in the US after performing at the Monterey Pop Festival, and with the top ten single "I Can See for Miles". They released The Who Sell Out at the end of the year, and spent much of 1968 touring the US.