@booksofwonder - The Sign on Rosie’s Door (1960) – “If you want to know a secret, knock three times.” Kathy does so and Rosie magically turns into a singer named Alinda. After the Fourth of July celebration, Alinda transforms back to Rosie, who finds she actually likes her original self. Also the basis of the musical, Really Rosie, on which Sendak collaborated with singer, songwriter Carole King.