Her biography of Frances Hodgson Burnett was originally published as Waiting for the Party (1974) and reissued in 2020 with the title Beyond the Secret Garden, with a foreword by Jacqueline Wilson.
Born in London, Ann Thwaite spent the war years in New Zealand, returning to complete her education at Queen Elizabeth's School For Girls, Barnet, and St Hilda's College, Oxford.
She has lectured in many countries, but most of her life has been spent as a writer; she eventually settled in Norfolk with her husband, poet Anthony Thwaite (1930–2021).
She edited (1968–75) Allsorts, an annual collection that included new work for children by such writers as Michael Frayn, James Fenton, Penelope Lively and William Trevor.
Her edition of Portraits from Life is a collection (1991) of Edmund Gosse's essays on his friends, including Henry James, Robert Louis Stevenson, and Thomas Hardy.