Ruth Dyson studied at the Royal College of Music where she later became Professor of Harpsichord, Clavichord and Fortepiano a post she held for twenty-three years. Many of her students, including Melvyn Tan, have gone on to glittering international careers. She was awarded a Fellowship in 1980.
She became well-known to continental audiences through her lecture tours for the British Council and to English audiences through her many public recitals and solo broadcasts on BBC Radio 3. She made a number of recordings for BBC Archives on early keyboard instruments from the Victoria and Albert Museum and from the Colt Collection and in 1972 represented Great Britain on the Jury of the International Fortnight in Bruges. She has lectured at the World Forum of the Harpsichord in Paris.
Her husband. Edward Thomas, worked for British intelligence in different capacities but with equal distinction throughout his life, during the Second World War as a naval intelligence officer and at Bletchley Park, afterwards at the Joint Intelligence Bureau, and latterly on the official history of British intelligence in the Second World War. They married in 1964 and he died 27 January 1996.
Her writings included articles in musical journals at home and abroad and she contributed the section on Piano for the 1983 edition of the New Oxford Companion to Music.
Her association with the Haslemere Festival and the Dolmetsch Summer School was an outstandingly happy one and went back to 1978. She died suddenly on Saturday 16th August, while attending the 1997 Dolmetsch Summer School in Haslemere, Surrey as director of early keyboard studies.