Petra Haden Sings: The Who Sell Out is the latest chapter in the always provocative, often unpredictable yet never less than fascinating musical career of Ms. Haden. The impetus for the project came from her friend, bassist Mike Watt (she provided vocals on his first solo outing as well as his most recent one, The Second Man's Middle Stand), who suggested that she attempt to re-imagine this classic Who album as an a capella album. (this at least a year before any news of Bjork's Medulla leaked to the press). He gave her an 8 track cassette tape with the original Who album recorded onto one track and the other seven empty, for her to fill with intricate vocal harmonies. Not only did Petra re-imagine all The Who's singing and instrumental parts ? including drums ? she also tackled all the interstitial mock radio commercials so integral to The Who Sell Outexperience. The final result is a technical tour de force that also invites a fuller appreciation of The Who's own achievement, bringing to the fore all the original elements of chorale music, vaudevillian schmaltz and Renaissance chamber ensemble playing.