"Once" by Morris Gleitzman is a poignant children's book that combines the themes of courage, survival, and friendship in a moving narrative. The story follows 9-year-old Felix, who has been living in an orphanage for over three years. His parents are not dead; they are struggling with the challenges of being a Jewish bookseller in Poland in 1942. When Felix witnesses the burning of Jewish books, he realizes the danger his family is in. Determined to warn his parents, he sets off and meets little Zelda, whose family has been murdered. Together, they embark on a journey that confronts them with the harsh realities of the time. This book is not only a captivating story but also an important lesson about history and the power of friendship.