Diamond's overall argument in this book is that some societies come to dominate others because of geographical luck. The book is meant as an answer to Yali's question. It is meant to explain why some societies became powerful and others did not. Some people have argued that this is because of racial characteristics or cultural characteristics of the various societies. But Diamond does not believe this. In the book, he argues that the societies that became powerful were simply lucky. They arose in places where farming was more likely to arise and to spread. This allowed them to form civilizations, which in turn gave them the technology, the political organization, and even the diseases that helped them dominate the other peoples of the world.