Susan Coolidge was a prominent American author in the late 19th century best known for writing books for children. Coolidge was a very prolific writer and her best known works are the five books that form the Katy Carr series about the coming of age of a young girl living in a small town in the Midwest. What Katy Did, published in 1872, is the first novel in the Katy Carr series. The action centers around Katy as a mischievous, twelve-year-old, tomboy who wants to change her ways and treat her five younger siblings with respect. What Katy Did at School, published in 1873, is the second novel in the Katy Carr series. The book follows Katy's adventures at boarding school as she meets a friend named Rose Red.