"The Mouse and the Motorcycle" is a children's novel by Beverly Cleary that tells the story of a young mouse named Ralph who lives in a hotel. Ralph dreams of adventure and finds a toy motorcycle belonging to a boy named Keith. When Ralph learns to ride the motorcycle, he discovers he can communicate with Keith, leading to a friendship filled with excitement. As Ralph and Keith embark on various escapades, they face challenges that test their bravery and resourcefulness. The story highlights themes of friendship, courage, and the importance of believing in oneself, making it a beloved tale for young readers.