Ruth Frow (28 July 1922 – 11 January 2008) was a peace activist and historian of the labour movement. She co-founded the Working Class Movement Library in Salford, a collection of material associated with labour and working class history.
 Ruth Engel was born on 28 July 1922 in St John's Wood in London. Her father, Leon Alfred Mayer Engel, was a concert pianist and a travelling sales representative in embroideries. Her mother, Ethel Maud Engel, was originally Irish catholic but converted to Judaism, her husband's faith, on their marriage. Ruth attended a Jewish synagogue, but had a largely secular upbringing, and she attended a local private girls’ school.
 The family moved to an estate built by a cousin, Engel Park in Mill Hill, when Frow was five. Her father died when she was thirteen.
 Upon leaving school, she enrolled in the Women's Auxiliary Air Force in April 1940, though underage, working in the RAF Fighter Command control room and on radar. Her altered date of birth is recorded in her discharge papers, along with a commendation of her service. She spent four and a half years in the WAAF. Here she met her first husband, Denis Edmund Haines, an electrical engineer, and the pair married on 25 July 1944. She left the WAAF when she became pregnant, towards the end of 1944.
 In 1945 she joined the Communist Party in Sandwich, Kent, on the recommendation from local miners to join over the Labour Party. She found the Communist Party an ideologically- and socially-attractive space as an activist and a woman not wishing to return to a purely domestic role post-war.
 Following the Second World War, Frow enrolled in the Emergency Teacher Training Scheme, and became a teacher in 1949. She was a trade union activist and member of the National Union of Teachers. She was Secretary of Teachers for Peace and Manchester branch of the Peace Committee, and was elected Vice-Chair of the Manchester Campaign for Nuclear Disarmament.
 In the 1950s she lived for a time with Communist party members Bill Wainwright and Molly Wainwright.
 She met her second husband, Edmund 'Eddie' Frow, in 1953 at a day school on labour history in Sussex, and they married in 1961. The pair were enthusiastic collectors of books, pamphlets and ephemera to do with labour history and the labour movement.
 The couple were both awarded honorary degrees from the University of Salford in 1989.
 Along with her husband Edmund, Frow was the founder of the Working Class Movement Library in Manchester. The library was originally the personal book collection of the couple, to which scholars or students of labour history could access for free. In 1972 the Frows established the library as a Charitable Trust, allowing it to be accessible as an education resource.
 Their collection of books and ephemera grew so extensive, in 1987 it was re-housed by Salford Council in a converted nursing home, in which it still retained; Jubilee House on The Crescent in Salford. The offer from the council was accepted over similar offers from universities, in order to avoided limited access for workers to their own history.
 In 1989 Ruth and Edmund Frow were awarded the Commendation of Merit by the Library Association for their service to the library profession.
 The Library is regarded as one of Britain's most important collections on working class history, with more than 30,000 rare books, pamphlets, photographs and other materials.
 Frow, often along with her husband Edmund, published extensively on historical and political issues. Her writings were aimed at a variety of wide audiences.
 Frow was a former Middlesex county junior tennis player.
 Ruth and Edmund Frow spent many years travelling Britain in a caravan, described in their book Travels with a Caravan. Before moving to a home in Salford, they lived in a flat within the library.
 Frow died January 11, 2008.  A a celebration of her life was held on 5 April 2008 at the Peel Hall at the University of Salford.
 The papers of Ruth and Edmund Frow are held in the Working Class Movement Library in Salford.