What are the motifs in Unbroken: A World War II Story of Survival, Resilience, and Redemption by Laura Hillenbrand?

Brutality of war is a recurring idea. Unbroken focuses on the story of Louis Zamperini and his particular experiences, but it paints an overall picture of the sometimes brutal and dehumanizing aspects of war. These are most evident in the descriptions of the treatment of prisoners by the Japanese. Louis Zamperini was beaten practically daily and sometimes tortured. Despite international agreements forbidding it, he and other prisoners were forced into slave labor. They were not allowed to send or receive letters from home. Many suffered from hygiene-related illnesses such as dysentery. Zamperini and others were subjects in medical experiments.