What is the theme in Empire of the Summer Moon: Quanah Parker and the Rise and Fall of the Comanches, the Most Powerful Indian Tribe in American History by S. C. Gwynne?

Major themes addressed in the book, Empire of the Summer Moon: Quanah Parker and the Rise and Fall of the Comanches, the Most Powerful Indian Tribe in American History, include the ability to adapt, the brutality of the Indians, and the importance of historical setting.