Born in 1906, Mary Gervaise (real name: Joan Mary Wayne Brown) was the daughter of accountant Alfred Wayne Brown, and his wife, Mary Elizabeth Boyden Lloyd, a classics graduate from Newnham, and a former teacher at Surbiton High School. Gervaise herself was educated in the junior department of Sutton High School, before being briefly sent to the religious boarding school Broadstairs, and then to Eversfield, in her hometown of Sutton. The Brown family moved to Exeter when she turned eighteen, to allow her to attend University there, but a diagnosis of anemia prevented such a course, and turned Gervaise' attention to writing. The family moved again, a few years later, eventually settling in Guilford, where Gervaise would live for the rest of her life. She died in 1998.
Gervaise’ first novel was serialized in the Family Herald, and was followed shortly thereafter by a second, The Fourth and Fenella (1928), which saw her entry into the school story genre. After a hiatus from writing during the Second World War, during which time she worked at a local hospital at a first aid post, Gervaise turned to the pony book genre, combining that with the girls' school story. She was a prolific author, and, in addition to her children's books, also published adult novels under the pseudonyms Hilary Wayne and Bellamy Brown.