In the three years since the release of Who By The Numbers, The Who foursome had undertaken solo projects and other individual interests. Finally reuniting after such an unusually long hiatus, they recorded Who Are You between late 1977 and early '78, in a variety of London-area studios. Without a doubt, everyone in the world would have welcomed recycled Who akin to their first decade of hits. But simple, catchy rock riffs were to be superseded in more complex subjects and daring arrangements. Pete Townshend's observations of moving on and saying farewell ("Sister Disco"), the creative process ("Guitar and Pen"), FM radio and its banal recycled music ("Music Must Change") and battles with alcohol ("Who Are You") are some of his most poignant writings. Bassist John Entwistle contributes three songs, the most in any one Who album. "905," "Had Enough" and "Trick Of The Light" reflect some of his finest, often-overlooked, work.
The album peaked at No. 2 on the pop chart in the U.S., most likely prevented from going No. 1 by the Grease soundtrack. The lone single released, the title song "Who Are You" would become a concert staple, often expanded into a jam for Townshend's guitaristics, and then be licensed out in 2000 for the opening theme to the hit television show CSI: Crime Scene Investigations.