The Nutcracker and the Mouse King is a classic children's book written by E.T.A. Hoffmann. It tells the story of a young girl named Clara who receives a nutcracker doll as a Christmas gift. The doll comes to life and takes Clara on a magical journey to the Land of Sweets, where she encounters the Sugar Plum Fairy and other enchanting characters. This delightful tale is often associated with the famous ballet adaptation and is a perfect read for the holiday season.