Josephine Pullein-Thompson is the daughter of writer Joanna Cannan and Captain Harold "Cappy" Pullein-Thompson. She was part of a large literary family that included her maternal aunt May Cannan, a poet, and cousin Gilbert Cannan, a novelist-playwright. She and her three siblings all became writers. Along with her sisters Christine Pullein-Thompson and Diana Pullein-Thompson, she is the author of many horse and pony books aimed mostly at girls, a genre established by their mother in the 1930s, which sold millions of copies. The three sisters wrote a collective autobiography, Fair Girls and Grey Horses: Memories of Country Childhood. Josephine also has written mystery books for adults, including Gin and Murder (1959), Murder Strikes Pink (1963) and They Died in the Spring (1960). She wrote A Place with Two Faces (1972) under the pseudonym Josephine Mann. She has long been involved with the British branch of PEN International. She was named a Member of the Order of the British Empire in 1984.