This is an excellent book, which by careful sleuthing, reveals a staggering amount of what pre-history cave art tells us about our forefathers. There are, however, two "yeah, but"s. The first is relatively trivial. Lewis-Williams suggests it is a conceptual leap to make 2D drawings from 3D life, yet he never discusses the most obvious thing in regard to this - shadows. The world of 2D shadows from 3D life is everywhere, and surely gave inspiration to early painters. The second is larger and broader. Much is made of "altered states of consciousness" which inspire the art, and the similarities in cultures across the world. Lewis-Williams suggest these are effectively delusions of the mind and the origins of spiritual experiences, which is a highly logical deduction. It is merely a shame, therefore, that he appears not to entertain an equally obvious alternate deduction - that the altered states themselves are not "delusions" but are universal experiences that speak of spiritual realities. There is no evidence here for - or against - the reality of a spirit world, but the casual reader may not be aware of this fact. Nevertheless, the book is an excellent, stimulating read that provokes thought in all but the most cloth-headed.