"The One and Only Ivan" is a children's novel by Katherine Applegate that tells the story of a silverback gorilla named Ivan who lives in a shopping mall. Ivan spends his days painting and observing the world around him, often reflecting on his life in captivity and his memories of the wild. The narrative is inspired by a true story and highlights themes of friendship, freedom, and the importance of animal rights. Ivan's life changes when a baby elephant named Ruby arrives, prompting him to reconsider his role and the possibility of a better life for them both.