 Diamond's first book, Guns, Germs, and Steel (1997), begins with the Columbian encounter.  Diamond asks why the Europeans conquered the Americans, rather than the other way around.  Assuming that the answer lies with Europe's technological advantage over the Americas, Diamond arrives at a second question.  Why, in the late 15th and early 16th centuries, did the Europeans have this advantage (1997, 15)? If all pre-historic peoples began roughly at the same starting point, this question implies a third: Why did pre-Columbian rates of development vary so much worldwide (16)?  Appealing to recent research in scientific anthropology, Diamond argues that environmental variation satisfactorily accounts for the corresponding social and technological variation.  Diamond defends the thesis that features of the natural environment, and the technology they directly enable, are the driving forces of long-run development (1997, 87). 