We all know that human history has proceeded very differently for peoples from different parts of the globe. In the 13,000 years since the last Ice Age, some parts of the world developed literate societies with metal tools, other parts developed only non-literate farming societies, and still others retained societies of hunter-gatherers with stone tools. Those historical inequalities have cast long shadows on the modern world, becuase the literate societies with metal tools have conquered or exterminated the other societies. While those differences constitute the most basic fact of world history, the reasons for them remain uncertain and controversial. This puzzling question of the their origins was posed to me twenty-five years ago in a simple, personal form.

In July 1972, I was walking along a beach on the tropical island of New Guinea, where as a biologist I study bird evolution. I had already heard about a remarkable local politician named Yali, who was touring the district then. By chance, Yali and I were walking in the same direction on that day, and he overtook me. We walked together for an hour, talking during the whole time.

Yali radiated charisma and energy... Many of the white colonialists openly despised New Guineans as "primitive". Even the least able of New Guinea's white "masters" as they were still called in 1972, enjoyed a far higher standard of living than New Guineans, higher even than charismatic politicians like Yali... He and I both knew perfectly well that New Guineans are on the average at least as smart as Europeans. All those things must have been on Yali's mind when, with yet another penetrating glance of his flashing eyes, he asked me, "Why is that you white people developed so much cargo and brought it to New Guinea, but we black people had little cargo of our own?"

"This book is the perfect antidote to the 'bell curve' theories of racial and ethnic discrimination. Drawing widely on geography, botany, zoology, archaeology, and epidemiology, Diamond shows us that human diversity is the result of historical processes, not differences in intelligence".

Kent V. Flannery, James B. Griffin Professor of Anthropological Archaelogy, University of Michigan