"Mr. Popper's Penguins" is a children's book written by Richard and Florence Atwater. It tells the story of a house painter named Mr. Popper who dreams of exploring the Arctic. His life changes when he receives a penguin named Captain Cook from an explorer, leading to a series of humorous adventures. As Mr. Popper and his family care for the penguin, they soon find themselves with more penguins, creating a lively and chaotic household. The story highlights themes of family, responsibility, and the joy of unexpected surprises, making it a beloved classic in children's literature.