Leonard Rosenman was born in Brooklyn, New York. After service in the Pacific with the Army Air Forces in World War II, he earned a bachelor's degree in music from the University of California, Berkeley. He also studied composition with Arnold Schoenberg, Roger Sessions and Luigi Dallapiccola.Rosenman composed the scores for such films as East of Eden (1955), Rebel Without a Cause (1955), Fantastic Voyage (1966), The Lord of the Rings (1978), Cross Creek (1983) and Star Trek IV: The Voyage Home (1986). He wrote incidental music for such television series as The Defenders, The Twilight Zone, Gibbsville and Marcus Welby, M.D. He also wrote the theme and almost all of the incidental music used for the entire run of the 1960s World War II television series Combat!. In the 1970s he composed Bass Concerto Chamber Music 4 for bassist Buell Neidlinger and four string quartets with a second bass.In his 70s Rosenman was diagnosed with Frontotemporal dementia, a degenerative brain condition with symptoms similar to Alzheimer's disease.He died March 4, 2008, of a heart attack at the Motion Picture & Television Country House and Hospital in Woodland Hills, California.