Excellent book, covering an astonishing array of studies & ideas-- although i agree with other review that it is somewhat scattershot in its aim for a reader base (swings from general sci reading to more academic).
one criticism-- the author uses humor quite a bit, mostly to great effect; however, the old men v. women joke made seemingly sympathetic to women is a reoccurring part of his humor arsenal. After being deployed yet again at some point during the discussion of the rise of language, i felt this irritated sense that maybe the analysis suffers somewhat as a result of this tendency.