Susan Coolidge (1835-1905) was born Sarah Chauncey Woolsey in Ohio, USA. She worked as a nurse during the American Civil War, after which she started to write. She is best known for her classic children's novel What Katy Did , which was modelled on her own family, and its four sequels: What Katy Did at School, What Katy Did Next, Clover and In the High Valley.