Sarah Chauncey Woolsey was an American children’s author who wrote under the pen name Susan Coolidge. She worked as a nurse during the American Civil War after which she started to write. Coolidge is best known for her classic children’s novel What Katy Did. The fictional Carr family was modeled after her own, with Katy Carr inspired by herself. The brothers and sisters were modeled on her four younger siblings: Jane, Elizabeth, Theodora, and William.