What are the motifs in Guns, Germs, and Steel: The Fates of Human Societies by Jared Diamond?

Conquest is a recurring idea. Though his discussion and examples, Diamond often focuses on conquest and how and why some groups have been able to dominate others. Although he does not go into great detail about the violence and oppression that happened when societies collided, conquest plays an important role in the overall theme of the book. In trying to explain why some groups held advantages over others, he is attempting to explain how it is that some groups were able to conquer others.