Louise Perkins Fitzhugh (October 5, 1928 – November 19, 1974) was an American writer and illustrator of children's books. Fitzhugh is best known for her 1964 novel ''Harriet The Spy'', about an adolescent girl who to keeps a journal recording the foibles of her friends, classmates, and captivating strangers. The novel was later adapted into a live action film in 1996. The sequel novel, ''The Long Secret'', was published in 1965, and its follow-up book, ''Sport'', was published posthumously in 1979. Fitzhugh also wrote ''Nobody's Family Is Going to Change'', which was later adapted into a short film and a Broadway musical.