In Guns, Germs, and Steel I asked why history has unfolded differently over the last 13,000 years in Eurasia, in the Americas, in sub-Saharan Africa, and in Aboriginal Australia, with the result that within the last 500 years Europeans were the ones who conquered Native Americans and Aboriginal Australians and sub-Saharan Africans, rather than vice versa.
Most of that book, was concerned with comparing the peoples of different continents, but I knew that I couldn't publish a book comparing the histories of different continents and considering Eurasia as a unit without saying something about the fascinating problem of the differences of history within Eurasia. Why, within Eurasia, was it Europeans who conquered the world and colonized other people, rather than the Chinese or the people of India or the Middle East? I devoted seven pages to that subject at the end of Guns, Germs, and Steel, and I think I arrived at the correct solution. Nevertheless, since the publication of Guns, Germs, and Steel, I've received a lot of feedback, and the most interesting feedback has been about the implications of that comparative analysis of the histories of China, Europe, India, and the Middle East.