Doreen Carwithen was born in Haddenham, Buckinghamshire on 15 November 1922. As a child she had her first music lessons from her mother, a music teacher, starting both piano and violin with her at the age of four. At age 16 she began composing by setting Wordsworth's "I Wandered Lonely as a Cloud (Daffodils)" for voice and piano.
In 1941 she entered the Royal Academy of Music and played the cello in a string quartet and with orchestras. She was a member of the harmony class of William Alwyn, who began to teach her composition. Her overture ODTAA (One Damn Thing After Another) was premiered at Covent Garden by Adrian Boult in 1947. The same year she was selected by the Royal Academy to train as composer of film music.
In 1961 she became William Alwyn's devoted secretary and amanuensis, becoming his second wife in 1975, adopting Mary Alwyn as her married name, as she disliked the name Doreen, and Mary was her middle name. She later worked as a Sub Professor of Composition at the RAM. After her husband's death in 1985, she founded the William Alwyn Archive and William Alwyn Foundation to promote his music and facilitate related research projects.
Doreen Carwithen wrote scores for over 30 films, including Harvest from the Wilderness (1948), Boys in Brown (1950), Mantrap (released in the U.S. as Man in Hiding) (1952), and East Anglian Holiday (1954). She also scored Elizabeth Is Queen, the official film of the coronation of Queen Elizabeth II.
She also composed orchestral music: an overture ODTAA (One Damn Thing After Another) (1945) (after the novel by John Masefield); a Concerto for piano and strings (1948); the overture Bishop Rock (1952) and a Suffolk Suite (1964). She also wrote two award-winning, but little-known, string quartets.
- To the Public Danger (1948)
- Burton-Page, Piers (2004). "Alwyn, William (1905–1985)". Oxford Dictionary of National Biography (Online ed.). Oxford University Press. doi:10.1093/ref:odnb/88725. Retrieved 2015-01-05. (subscription or UK public library membership required)
- London Symphony Orchestra, Richard Hickox, Chandos records 9524.
- Sorrel Quartet, Chandos Records: 9596.
- London Symphony Orchestra, Richard Hickox, Chandos Records: 9196.