Many arguments in ''Guns'' were dazzling. Diamond showed, for example, that as the last ice age ended, by chance Eurasia held many plants that could be bred for controlled farming. The Americas had few edible plants suitable for cross-breeding, while Africa had poor soil owing to the millions of years since it had been glaciated. Thus large-scale food production began first in the Fertile Crescent, China and Europe. Population in those places rose, and that meant lots of people living close together, which accelerated invention; in other locations the low-population hunter-gatherer lifestyle of antiquity remained in place. ''Guns'' contends the fundamental reason Europe of the middle period could send sailing ships to explore the Americas and Africa, rather than these areas sending sailing ships to explore Europe, is that ancient happenstance involving plants gave Europe a food edge that translated into a head start on technology. Then, the moment European societies forged steel and fashioned guns, they acquired a runaway advantage no hunter-gatherer society could possibly counter.