The documentary explores the enigmatic music and life of Harry Nilsson within a effort to answer this query,"Who is Harry Nilsson?" The film contains 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 music videos, promotional films, and home pictures. Segments from the unreleased documentary made through the listing of Son of Schmilsson (Did Someone Drop His Mouse?) . And excerpts from Nilsson's rare television looks within his BBC cries, the"Smothers Brothers Comedy Hour","Playboy After Dark", also within a event of"The Ghost and Mrs. Muir".