This intriguing and expansive book gathers knowledge from a number of fields (archaeology, anthropology, ecology, evolutionary biology, horticulture, and more). Its novelty is not in the details, any of which can be found in other books, but in the synthesis of 13,000 years' worth of human history. Diamond argues that many (but not all) of "the striking differences between the long-term histories of peoples of the different continents have been due not to innate differences in the people themselves but to differences in their environments."
Diamond covers so much material that any attempt at summary would be imprecise. The sections I found most compelling dealt with agriculture and animal husbandry--two topics that would have probably induced sleep if covered by another author. For example, he presents the fascinating background that the dominant five "large" domesticated mammals--sheep, goats, cattle, pigs, and horses--originated in central Eurasia (and that no easily domesticated, large mammals were available, for example, to North Americans or Australians); that these animals include the world's only widespread "beasts of burden," giving their human handlers additional advantages in mobility and farming; and that most of the world's lethal diseases resulted from proximity to the barnyard, gradually providing Eurasians with immunity to illnesses that later wiped out entire societies upon first exposure. The minor mammals (camels, llamas, reindeer) were too limited by geography and climate to affect the course of history outside their confines. As for zebras, bears, giraffes, tigers, hippos--to this day, nobody has been able to domesticate them. While this seems intuitively obvious, no writer has so clearly and irrefutably connected the dots, showing how access to these animals gave early chiefdoms an insurmountable advantage over those human societies without them and allowed them to develop surpluses and commerce that supported the world's most enduring civilizations.
Comments made by the author's critics, while few in number, nearly prevented me from reading this book and need to be addressed so other readers won't be similarly discouraged. A few readers seem offended by Diamond's self-mocking and somewhat tongue-in-cheek assertion (in the Introduction) that the natives of New Guinea have certain advantages that make them arguably more "intelligent." Yet these commentators are willfully ignoring the context: Diamond admits that "New Guineans tend to perform poorly at tasks that Westerners have been trained to perform since childhood," yet he is quite aware of how "stupid I look to New Guineans when I'm with them in the jungle." That is, if one defines "intelligence" not as the knowledge needed to use a computer or write a book review but, rather, as the ability to survive in the wild ("following a jungle trail" or identifying poisonous mushrooms, to cite two of the author's examples), then the New Guineans win hands down. To make a similarly lighthearted argument: when the house of cards we call "civilization" is threatened by the least misfortune (economic recession, power blackout, bad weather, the death of a British princess), a frightening number of otherwise "intelligent" people, instead of relying on their wits and survival skills, rush straight for their therapists.
Likewise, anyone who accuses Diamond of "geographic determinism" cannot have read the epilogue, in which he clearly rejects such an extreme position. He admits that individuals and cultures--and, for that matter, pure chance--can also influence history, but "that some environments provide more starting materials, and more favorable conditions for utilizing inventions, then do other environments." The author's argument is unambiguous: while culture, as well as individual inventors and rulers, certainly influence history on a microcosmic level (during spans of centuries or millennia), there are larger factors, such as geography and ecology, at play when human history is considered as a whole over the last 13,000 years. Diamond is looking at the forest rather than the trees; thus, to fault the author for ignoring such factors as religion and politics is off the mark, since such belief systems didn't exist in anything remotely resembling their present form for most of the period under discussion. Furthermore, to identify human advances in terms of culture still fails to explain how differing cultures arose in the first place.
Finally, and more easily dismissed, are those hecklers who howl "political correctness." Such critics seldom identify flaws in the author's arguments or even tell us what they insinuate by this increasingly meaningless term.
Since the book's span is so sweeping and since many of Diamond's hypotheses are offered tentatively (as suggestions for a new "science" of history), there are bound to be statements or implications that may eventually prove inaccurate or too simplistic. I strongly suspect, however, that his overarching thesis will withstand the test of time; at the very least, "Guns, Germs, and Steel" will inspire open-minded thinkers to consider human history--in its broadest sense--in a whole new light.