There are several broad explanations in world history about why the world is the way it is today. Jared Diamond in Guns, Germs, and Steel takes a very long perspective which emphasizes the importance of geography and environmental factors. Others, including William H. McNeil, have emphasized more the explanatory importance of culture, politics, and individual agency in shaping the course of history.
Guns, Germs, and Steel Book Review by Anatoly Karlin
The New York Review – Jared Diamond and reply by William H. McNeil