Admirably concise, this book covers all relevant issues in less than 170 dense but very enjoyable pages, not one of which is wasted. Through logical arguments, it successfully challenges (and comes close to completely demolishing) several long-held assumptions regarding early humans, particularly the so-called "savannah hypothesis", which he believes should concede defeat to the "aquatic hypothesis", and the "kin selection" theory, which he convincingly claims to be deeply flawed. Instead of concentrating on a single aspect of primitive societies (e.g. stone tools or bone structure), the author navigates interdisciplinary waters with great dexterity, pulling together strands from various specialized fields in order to support a series of coherent, clear-cut conclusions. Only the last chapter (regarding morals and social interaction) is a bit lacking in clout, and better dealt with elsewhere, but the rest of the book is a real tour de force, and I would be surprised to find a better introduction to current thinking in paleoanthropology. This should be mandatory reading for anyone even remotely interested in the field.