Dorothea Moore was born in the borough of Islington, London, England, the daughter of a clergyman and his wife. She was educated at the Godolphin School in Salisbury and Cheltenham Ladies' College. During World War I, she served in the Voluntary Aid Detachment (VAD) and settled in Eastbourne afterward, keeping house for her brother, a physician. Miss Moore was a prolific writer, producing popular books for young people, especially girls. These included historical novels, tales of girls at school, and stories about Girl Guides. She is credited with writing the first Guiding story for girls, Terry the Girl Guide (1930). She herself was an adult Guider from 1918 to 1927, and ran a Brownie pack from 1918 to 1928. Two of Miss Moore's plays, My Lady Bellamy and Grey Mask, were performed by a professional acting troupe, the Alexander Maclean Company, and it's possible that she also toured with them.