I promised some further comments about Jared Diamond's Guns, Germs and Steel so here goes.
The aim of this book is to explain why the denizens of Australasia, the Americas and Africa got colonised by the denizens of Eurasia and not the other way around. But the explanation must not postulate any sort of racial differences between people. This is fine as racial differences are so slight (aside from appearance and disease resistance) that they are very unlikely to have any effect on history. Unfortunately, Diamond himself is a reverse racist who gives some folk-evolutionist reason why he thinks New Guinean hunters are probably cleverer than American couch potatoes. This grates a bit as does his calling Spanish conquistadors "murderous" and guilty of "genocide" while his beloved cannibals get off scot-free. When he reveals in the very last chapter that black Bantu farmers did exactly the same thing to pygmies and Khosian herders as Europeans did in America you can almost see his hands wringing. However, this stuff does not detract from Diamond's arguments.
The interest of this book is that it represents an attempt to actually do what Fernand Braudel only talked about. For those who have not sat a "theory of history" course and don't know about the Annales school, Braudel suggested that the geography of the Mediterranean basin shaped the cultures that live there. So, in his opus The Mediterranean in the Time of Phillip II he begins with a long description of the landscape and topology. However, many critics have felt he failed to link this to the rest of the book and really show how it all affected the cultures and history he was studying. Jared Diamond, however, ably shows how long term biogeographical processes translate into human history. For this he deserves congratulations.
Let me say from the outset that I think he is largely right. His explanation is simply stated: Eurasia had a larger number of wild plants and animals that could be domesticated. This gave rise to a head start and allowed civilisation to develop more quickly. Also, the east/west axis of Eurasia meant ideas could spread easily over a wide area as the climate was similar all along the way. Other areas had no animals to domesticate (because the first humans hunted them to extinction in America and Australia), no useful plants and a north/south axis that made diffusion difficult. Also, domestic animals provided the breeding ground for the epidemics that decimated native populations. Finally, Eurasia is much bigger that other continents which produced more cultures to learn from each other and compete in a way that meant they were encouraged to try new ideas.
For the Americas and Australasia, I find this 100% convincing while for Africa I am slightly less convinced. Diamond also hardly explains why it was the north western corner of Eurasia that did most of the colonising and not India, China or elsewhere. That said, this is a book well worth reading and its ideas should be built on in the future.