Susan Coolidge was a Civil War nurse who never had a family, and still she was able to capture the heart of children. What Katy Did is her best-known work. Katy Carr and her family lived in the 1860's. Katy wants to be beautiful but she is a tomboy always who is getting into mischief. She is injured in an accident and her recovery gives her the time she needs to learn to be kind and good lthe way she had always dreamed of being.