Susan Mary Cooper is an English author of children's books, born on 23 May 1935 in Burnham, Buckinghamshire. She is best known for The Dark Is Rising, a contemporary fantasy series that incorporates British mythology, including Arthurian legends and Welsh folk heroes. This series earned her the Margaret A. Edwards Award from the American Library Association in 2012, recognizing her contribution to writing for teens. In the 1970s, two novels from the series were named the year's best English-language book with an authentic Welsh background by the Welsh Books Council. In 2024, she was named the 40th Damon Knight Memorial Grand Master by the Science Fiction and Fantasy Writers Association for her significant contributions to the literature of science fiction and fantasy.

Susan Cooper grew up in the green countryside of Buckinghamshire, which is now part of Greater London. Her early love for reading was shared with her younger brother, who also became a writer. After attending Oxford University, where she became the first woman to edit the university's newspaper, Cooper worked as a reporter and feature writer for London's Sunday Times. Her first boss was Ian Fleming, the creator of James Bond. Cooper wrote her first book for young readers, "Over Sea, Under Stone", in response to a publishing house competition, which later became part of her critically acclaimed five-book fantasy sequence, "The Dark Is Rising".