In spite of its title, this book is only partly about the Neanderthals; a good deal of space is taken up with descriptions of the changes that have taken place in the flora and fauna of the Iberian peninsula.
There are three sections. The first provides an overview of what is currently known, or surmised, about human evolution from our African origins through the Australopithecines, Homo habilis, Homo ergaster, and Homo erectus. The Neanderthals arose from this lineage. Modern man is described as having arrived about 40,000 years ago from Africa, so Arsuaga subscribes to the "out of Africa" hypothesis for our own origin, though he does not really discuss this still slightly contentious issue.
The average height of the Cro-magnons, Arsuaga says (quoting two Italian authors), was about 5'9" for men and 5'4" for women. This is quite a bit less than the 6' often cited by other authors but unfortunately Arsuaga does not comment on this discrepancy. He feels able to state fairly confidently that the Neanderthals had light skins while the Cro-magnons were darker. His reason for this that the Cro-magnons, having recently come from Africa, would have dark skins to protect them against skin cancer, while the Neanderthals needed white skin to produce vitamin D. However, the vitamin D hypothesis is not universally accepted (see, for example, Christopher Wills's disucssion of this in The Runaway Brain).
The middle section of the book contains three chapters which are mainly about the Iberian peninsula in prehistory. Arsuaga admits that this may not relevant for everyone and says that it could be skipped; I found it interesting myself, because I know Spain, but even so I could have done with a few maps to make it easier to identify the various regions. The third section is in many ways the most original and important part of the book, because it contains an account of the findings at a remarkable site called Sima de los Huesos (the "Bone Pit"). Excavations here are still continuing, but so far they have yielded more than four thousand human fossils; very much more remains to be discovered. These individuals were Neanderthals or proto-Neanderthals. It is very unusual to find so many Neanderthal skeletons in one place; Arsuaga suggests that they may even have died at the same time, perhaps because of famine or disease.
The book is written in an informal, even chatty, style and is not without appeal. Arsuaga clearly has acquired an affection for the Neanderthals, who he thinks have something to teach us, and there are numerous nuggets of fascinating information about them. There are, however, better and more comprehensive books about the Neanderthals and the lengthy account of prehistoric Iberia probably tells many non-Spanish readers more than they really want to know about the subject. The translation is mostly adequate but in a few places the sense of the Spanish seems to have been missed, and there are some silly typographic slips. We should not find "echinoderms" being rendered as "equinoderms" in a scientific text, nor should "articular surface" appear as "auricular surface". Alfred Russel Wallace comes out as Alfred Russell Wallace, Megatherium becomes Magatherium, and there is no excuse for perpetrating the illiterate neologism "irregardless".
Related review: In Search of the Neanderthals, by Christopher Stringer and Clive Gamble.