''Charlotte Sometimes'' is a children's novel by British writer Penelope Farmer. It is the story of Charlotte, a young girl sent to a boarding school where she begins travelling back in time every other night, switching places with a girl called Clare. Alternating between 1963 and 1918, the book takes a frightening turn when the girls find themselves stuck in the wrong decades.
Notable for its philosophical themes and questions of identity and self, the book inspired Robert Smith of Music/TheCure to write the song ''Charlotte Sometimes''.
* AnnoyingYoungerSibling - Clare's little sister Emily initially fits this trope, though Charlotte later grows fond of her.
* BoardingSchool - Largely set in one.
* MistakenIdentity - Though in a decidedly non-hilarious manner. Charlotte and Clare are forced to figure out how to live each other's lives while not revealing to anyone what's going on.
* RevisedEnding - in the 1985 version of the book a few scenes are removed, including an emotional one at the end.