This is a picture book biography of Sarah Emma Edmonds, a Canadian-born woman who served as a spy in the Union Army during the Civil War. Edmonds's story has natural appeal. After coming to America, teenage Edmonds posed as a man, eventually lying her way into a post as a male battlefield nurse in the Union Army at age 17. Several times she posed as woman or as a slave (or both) and snuck behind Confederate lines. Since no one in her company knew she was actually a woman, many of her disguises required her to pretend to be a man pretending to be a woman. Eventually, she published her memoirs, was granted a federal pension, and became the only woman granted membership in the Civil War veterans group, the Grand Army of the Republic.