«Charlotte Sometimes» is a children's novel by Penelope Farmer, published in 1969. The story is centred around a girl called Charlotte, who, not long after starting at a boarding school, finds that she has mysteriously travelled back more than forty years. The teachers and other students call her "Clare", the girl in whose shoes Charlotte finds herself. Charlotte and Clare mysteriously exchange places each night, each one alternating between the years 1918 and 1963. Although Charlotte and Clare never meet each other, they communicate with one another by writing notes. The girls are faced with the disconcerting scenario of finding out how to live each other's lives without being discovered.