The documentary explores the enigmatic life and music of Harry Nilsson in an attempt to answer the question, *Who is Harry Nilsson?* The film includes new and archive audio and film including interviews with Robin Williams, Yoko Ono, Van Dyke Parks, Randy Newman, Ray Cooper, the Smothers Brothers, and Micky Dolenz. *Who is Harry Nilsson?* uses promotional films, music videos, and home movies; segments from the unreleased documentary made during the recording of Son of Schmilsson (Did Somebody Drop His Mouse?); and excerpts from Nilsson*s rare TV appearances in his BBC specials, the *Smothers Brothers Comedy Hour*, *Playboy After Dark*, and in an episode of *The Ghost and Mrs. Muir*. Written by Roger Smith