What Katy Did is an 1872 children's book written by Sarah Chauncey Woolsey under her pen name Susan Coolidge. It follows the adventures of a twelve-year-old American girl, Katy Carr, and her family who live in the fictional lakeside Ohio town of Burnet in the 1860s. Katy is a tall untidy tomboy, forever getting into scrapes but wishing to be beautiful and beloved. When a terrible accident makes her an invalid, her illness and four-year recovery gradually teach her to be as good and kind as she has always wanted.
Two sequels follow Katy as she grows up—What Katy Did at School and What Katy Did Next. Two further sequels relating the adventures of Katy's younger siblings were also published—Clover and In the High Valley. Although these were long out of print, they have now been reprinted and are available online.
Coolidge modeled Katy on her own childhood self, and the other 'Little Carrs' on her brothers and sisters