Trudy Bliss was the keeper of the flame for her husband, the composer Sir Arthur Bliss, for 33 years after his death in 1975, and a writer and broadcaster who enjoyed success at the end of the war and in the postwar period. In 1987 she founded the Bliss Charitable Trust to promote performance and recording of her husband’s music and to encourage young composers.

Sir Arthur, who adroitly combined the modern with the romantic, is best remembered for his thrilling, martial score for Things to Come (1935), Alexander Korda’s film of H. G. Wells’s futuristic story. Perhaps the finest of his works is his choral symphony Morning Heroes (1930), which evokes his First World War experiences including being wounded on the Somme and gassed at Cambrai, and the death in battle of his brother Kennard.

Trudy Bliss was born Gertrude Hoffmann in 1904 in Belmont, Massachusetts. Her father, Ralph Hoffmann, was a naturalist who founded the Natural History Museum in Santa Barbara, California, where the family settled in 1919. While Trudy was appearing in an amateur dramatic production in Santa Barbara in 1924 she met Arthur Bliss, then 33 and himself half American. They were married the following year and moved to London.

Trudy was so taken with her husband’s composing that she studied music theory herself at the Royal College of Music and took singing lessons. Sir Arthur dedicated his Serenade for Orchestra and Baritone — a work in praise of love — to her in 1929.

When the war broke out the Blisses and their two daughters were on holiday in New England after the premiere of his piano concerto written for the New York World Fair. Sir Arthur was appointed visiting professor at the University of California, Berkeley, but in 1941 he left his family in the US and returned to London to work first as assistant overseas music director at the BBC and then as the corporation’s Director of Music. As the war progressed, Trudy, an instinctive broadcaster, contributed US recipes to a BBC programme called The Kitchen Front.

This led to her co-authorship with Alexie Gordon of Come into the Kitchen (1946), a book of recipes for children brought up on wartime rationing. Towards the end of the war she made weekly broadcasts about aspects of British life for the BBC’s North American service.

From broadcasting she turned to writing, and in 1949 Gollancz published Jane Welsh Carlyle — A Selection of Her Letters, chosen with a scholarly commentary by Trudy Bliss. She followed this four years later with Thomas Carlyle: Letters to his Wife, also published by Gollancz.

In addition to Things to Come — one of the earliest film scores to take on a life of its own in the concert hall — Arthur Bliss is widely esteemed today for his score for the chess ballet Checkmate (1937) and his Music for Strings, which was given its premiere by Adrian Boult and the Vienna Philharmonic Orchestra at the Salzburg Festival in 1935. Sir Arthur was knighted in 1950, appointed Master of the Queen’s Musick in 1953 and made a Companion of Honour in 1971.

Lady Bliss is survived by her two daughters.

Lady Bliss, writer, broadcaster and the widow of Sir Arthur Bliss, was born on April 2, 1904. She died on November 21, 2008, aged 104