Ralph R. Greenson (born Romeo Samuel Greenschpoon, September 20, 1911 – November 24, 1979) was a prominent American psychiatrist and psychoanalyst. Greenson is famous for being Marilyn Monroe's psychiatrist, and was the basis for Leo Rosten's 1963 novel, Captain Newman, M.D.. The book was later made into a movie starring Gregory Peck as Greenson's character. There has been much conjecture, by investigating officers, press and the public, about Greenson's involvement in a possible cover-up concerning the circumstances of Monroe's death.Greenson was well known for his early work on returning WWII soldiers suffering from Post Traumatic Stress. He also had other famous clients, such as Tony Curtis, Frank Sinatra, and Vivien Leigh. Greenson and his wife, Hildi Greenson, were the darlings of the Southern California psychoanalytic community, intellectuals and with certain notables in the entertainment industry. They were good friends with Anna Freud, Fawn Brodie and Margaret Mead.