"The One and Only Ivan" is a children's novel by Katherine Applegate that tells the story of a silverback gorilla named Ivan. Living in a shopping mall, Ivan spends his days painting and observing the world around him. He longs for freedom and a better life, reflecting on his past and the animals he shares his space with. The story also features Ruby, a young elephant who arrives at the mall and inspires Ivan to take action. Through their friendship, Ivan learns the importance of hope and courage, ultimately leading him to seek a way to escape and help his fellow animals.