(written from a Production point of view)
Leonard Rosenman (7 September 1924 – 4 March 2008; age 83) was the Academy Award and Emmy Award-winning composer who wrote the music score for Star Trek IV: The Voyage Home. For this score, he earned an Academy Award nomination (his fourth) and won an ASCAP Award from the American Society of Composers, Authors and Publishers.
Born in Brooklyn, New York, Rosenman moved to California following World War II. A skilled piano player since his teenage years, Rosenman began studying music composition with composers Arnold Schoenberg and Roger Sessions. Afterward, in 1952, Rosenman studied with Italian composer Luigi Dallapiccola in Massachusetts.
Rosenman was teaching piano and writing chamber music in New York when film director Elia Kazan approached him to compose the score for the acclaimed 1955 film, East of Eden. Following this film, Rosenmann composed for such classic films as Rebel Without a Cause (1955, featuring Corey Allen, Ian Wolfe, Chuck Hicks and photographed by Ernest Haller), Pork Chop Hill (1959, featuring Biff Elliot, Barry Atwater, Ken Lynch, Paul Comi, Bert Remsen and William Wellman, Jr.), Fantastic Voyage (1966, story by Jerome Bixby), and Stanley Kubrick's Barry Lyndon (1975, featuring Steven Berkoff). He won his first Academy Award for the latter film, and won a second for 1976's Bound for Glory (starring Ronny Cox and Gail Strickland and featuring Bobby Bass). A third Academy Award nomination came his way for 1983's Cross Creek (starring Alfre Woodard and featuring Ike Eisenmann, Malcolm McDowell and cinematography by John A. Alonzo), and he received his fourth and final Academy Award nomination for Star Trek IV.
In addition, Rosenman earned two Emmy Award nominations – winning both – for his scoring of the TV movies Sybil (1977) and Friendly Fire (1979, featuring Paul Baxley). He also received a Golden Globe nomination for scoring the 1978 animated adaptation of J.R.R. Tolkien's Lord of the Rings (featuring Lou Elias, Felix Silla and Dennis Madalone).
Rosenman's other film scoring credits include The Cobweb (1955), The Savage Eye (1960), Hell Is for Heroes (1962, featuring Chuck Hicks), Countdown (1968, featuring Steve Ihnat, Ted Knight and Garrison True), and A Man Called Horse (1970, starring Judith Anderson). He also scored the two of the Planet of the Apes sequels, 1970's Beneath the Planet of the Apes (featuring Jeff Corey, James Gregory and Lou Wagner) and 1973's Battle for the Planet of the Apes (featuring France Nuyen, Paul Williams, David Gerrold and cinematography by Richard H. Kline). More recent credits include 1980's The Jazz Singer, 1990's Robocop 2 (starring Peter Weller and featuring John Glover), and 1994's The Color of Evening (featuring Bill Erwin). He also scored for episodic television, including The Defenders, Combat!, and Marcus Welby, M.D., and even an episode of The Twilight Zone.
In his later years, Rosenman suffered from Frontotemporal dementia, a degenerative brain condition similar to Alzheimer's disease. Regardless, Rosenman continued to compose music into his 80s. He died of a heart attack at the Motion Picture & Television Country House and Hospital in Woodland Hills, California at the age of 83. A memorial service was held for Rosenman on 28 April 2008. Among those in attendance was Star Trek film director and writer Nicholas Meyer and TOS guest actor Robert Brown, the latter of whom was a close friend of Rosenman's. Brown also spoke at the service, relaying his memories of the times he spent with Rosenman. 
Rosenman is credited with helping to modernize film music in the 1950s and 1960s. Through the application of modern techniques not commonly used at the time, Rosenman brought a more contemporary approach to film composition.