Sarah Chauncey Woolsey was an American children's author who wrote under the pen name Susan Coolidge. Woolsey was born January 29, 1835, into the wealthy, influential New England Dwight family in Cleveland, Ohio.She edited The Autobiography and Correspondence of Mrs. Delaney (1879) and The Diary and Letters of Frances Burney (1880). She is best known, however, for her classic children's novel, What Katy Did (1872). The fictional Carr family was modeled after the author's own, with Katy Carr inspired by Susan (Sarah) herself, and the brothers and sisters modeled on Coolidge's four younger Woolsey siblings.