Having read Charles C. Mann's 1491 immediately before Guns, Germs, and Steel, I was all-too aware of the dated nature of many of Diamond's assumptions about the New World. (And therefore I would highly recommend 1491 to anyone interested in learning about the latest and greatest developments in knowledge concerning the early history of the Americas.) This seed of doubt concerning the accuracy of Diamond's assumptions about the Americas prevented me from fully appreciating what he had to say about the histories of the other continents, of which I am even less familiar.

True, the theories promoted in Diamond's book are not disrupted by the accuracy of details concerning the peoples and societies under discussion, but this raises another concern for me: the theories are so generalized, they don't suffer for the potential inaccuracy of described events. In other words, instead of starting with objective histories (and or/references to ongoing research into such histories), the book starts with a central premise and cites historical examples to support that theory.

The central theory may be summarized as follows:
* People with agriculture can produce food surpluses
* Food surpluses can support larger populations
* People located in geographical areas with animals to domesticate were able to use such animals for labor as well as meat
* Large populations with food surpluses can support artisans and bureaucrats
* Artisans and bureaucrats lead to more complex social structures and technical innovations (tools, weapons, metallurgy)
* Dense populations (especially those with domestic animals) contract and evolve immunities to germs and diseases
* Eurasian populations, due to favorable conditions for agriculture and their head-start on many other populations around the globe, acquired the "guns, germs, and steel" to conquer populations lacking the equivalent weaponry, diseases, and technology.

While the central premise makes general sense, I think it's important to acknowledge that it represents a generality, and thus offers an over-simplified view of human history. Considering the fact that this book leans so heavily on theory, I am surprised that book stores typically shelve it in History and Science sections, rather than Philosophy.

After that long disclaimer, I can say that the overall content was interesting. I especially enjoyed the section about the process of domesticating plants and animals. It had never really occurred to me that some plants and animals simply cannot be domesticated, or that the yields of some plants made the domestication of others less desirable or completely unnecessary.