A nice read about several topics in the evolutionary history of humans. Since I have read several other books in this area recently, not much was new for me, but I think this is a good book for those who want an introduction. The writing is mostly fluid and easily read.
Towards the end of the book he poses the question why humans reached "modernity" (by which he means, I think, a material and artistic culture that produced artifacts) much later than Homo sapiens became clearly the same species as we are today. That is, why the lag time? His interesting suggestion is that it has to do with population size. Cultural transmission benefits hugely from a larger population size. Conversely, a too small population makes it very hard to maintain a certain cultural level. The standard example here is the Tasmanian indigenous culture, which after having been cut off from Australia, clearly regressed.
However, this suggestion somewhat begs the question. Why did the population increase? Could cultural advances have caused this, or was it just (?) due to external causes, such as climate change?
Minor quibble: Rutherford discusses rape as a phenomenon, and argues that although very similar behavior (i.e. violently enforced sex) can be seen in some other species, such as dolphins, those instances should not be called "rape" since that is a legal term. I am not so sure. Rutherford does not want to anthropomorphize, but here I think he goes too far in the other direction.