"What Katy Did" is a childrens book written by Sarah Chauncey Woolsey under her pen name "Susan Coolidge". It was published in 1872 and follows the adventures of a twelve-year-old American girl named Katy Carr and her family who live in the fictional lakeside Ohio town of Burnet in the 1860s. Katy is a tall, untidy tomboy who is constantly getting into scrapes but wishes to be beautiful and beloved. The book was followed by four sequels: "What Katy Did at School," "What Katy Did Next," "Clover," and "In the High Valley". In 2015, author Jacqueline Wilson wrote a modern retelling of "What Katy Did" titled "Katy," which was adapted into a CBBC TV series in 2018. The book has been reprinted many times and is considered a classic childrens novel.