He makes the “nature” explanation for the shape of culture, against the “nurture” case we are more used to from historians, economists, and social scientists of all types. Good insights which are new to me, such as the role of the north-south continental axis in slowing down the propogation of domesticated plants. But there is a hundred pages at least of redundancy here, and I notice many of the chapters originally appeared as articles in journals. I wish he had edited harder.
I have one nitpick: he glides over political distinctions. This passage, for example:
Guns, Germs, and Steel (Jared Diamond)
Kindle Loc. 4786-89
We consider George Washington a statesman because he spent tax money on widely admired programs and did not enrich himself as president. Nevertheless, George Washington was born into wealth, which is much more unequally distributed in the United States than in New Guinea villages. For any ranked society, whether a chiefdom or a state, one thus has to ask: why do the commoners tolerate the transfer of the fruits of their hard labor to kleptocrats? …
==========
…in the entire book, as far as I can tell, he recognizes no distinction between taxes, by consent, and tribute, which is forced taxation without consent. It all just results in some equation of poverty and wealth and that end result seems to be the only moral dimension he cares about. This blindness makes me nervous about his arguments in areas I am not competent to judge.
TimothyOne 
Diamond’s book is a little out of date on genetics. Recent studies have shown that there was an increase in genetic change with the development of agriculture and population expansion in eurasia. Some of these changes appear to relate to neurological function (see papers by Benjamin Voight, Bruce Lahn or Scott Williams).
New York Times science writer Nicholas Wade’s book ‘Before the Dawn’ covers some of this, as does the more recent ‘The 10,000 Year Explosion: How Civilization Accelerated Human Evolution’.