This book should win some kind of award specifically for being a dull, worthy book made incredibly popular through briliant naming. The fundamental thesis is that the rise of civilisation in different parts of the world was controlled by the crops and animals available for domestication, and then the spread of these and related ideas. In other words, it's pretty predetermined by geography, and this is why Eurasia had the edge, and it's nothing to do with human genetics. Happily, as well as being a politically correct view, it's argued carefully and scientifically.
As well as the fundamental thesis, there's various interesting other bits and pieces. For example, while different parts of humanity don't have a natural intelligence advantage, the ideas they have and domesticated species they have do give them an advantage. In other words, there's natural selection based on the ideas and technology used. It's the ideas fighting it out, rather than genes as in other species. The humans involved are just being carried along! This seems a nice example of 'meme's.
Another thing that's interesting is how long we've been having a major impact on the world for. Admittedly, we seem to be having an exponentially increasing effect, but we've still had plenty of impact for thousands of years. There seems to be strong evidence that we've been wiping out big animals through hunting for tens of thousnds of years. Deserts? Generally seem to have us involved, too.
As I said at the start, the title makes this thing sound far more interesting than it really is. It's overly long, and slightly tedious in places, but... well, the overall idea is good, it's well-explored and there are plenty of interesting side-issues explored. Perhaps it needed a bit more editing?