Really Rosie is a musical with a book and lyrics by Maurice Sendak and music by Carole King. The musical is based on Sendak's books Chicken Soup with Rice, Pierre, One was Johnny, Alligators All Around (which compose 1962's The Nutshell Library), and The Sign on Rosie's Door (1960). Sendak based the story on a demonstrative little girl who used to sing and dance on the stoop of her building, whom he observed while he was a little boy growing up in Brooklyn.