The ethnobotanist co-author of Psilocybin: The Magic Mushroom Grower's Guide (not reviewed) puts forth the theory that magic mushrooms are the original ``tree of knowledge'' and that the general lack of psychedelic exploration is leading Western society toward eventual collapse or destruction--controversial statements, to say the least, though the argument's details often prove fascinating. In the beginning, McKenna tells us, there were protohumans with small brains and plenty of genetic competition, and what eventually separated the men from the apes was an enthusiasm for the hallucinogenic mushrooms that grew on the feces of local cattle. Claiming that psilocybin in the hominid diet would have enhanced eyesight, sexual enjoyment, and language ability and would have thereby placed the mushroom-eaters in the front lines of genetic evolution--eventually leading to hallucinogen-ingesting shamanistic societies, the ancient Minoan culture, and some Amazonian tribes today--McKenna also asserts that the same drugs are now outlawed in the US because of their corrosive effect on our male-dominated, antispiritual society. Unconsciously craving the vehicles by which our ancestors expanded their imaginations and found meaning in their lives, he says, we feast on feeble substitutes: coffee, sugar, and chocolate, which reinforce competition and aggressiveness; tobacco, which destroys our bodies; alcohol, whose abuse leads to male violence and female degradation; TV, which deadens our senses; and the synthetics--heroin, cocaine and their variations--which leave us victimized by our own addiction. On the other hand, argues McKenna, magic mushrooms, used in a spiritually enlightened, ritual manner, can open the door to greater consciousness and further the course of human evolution- -legalization of all drugs therefore is, he says, an urgent necessity. Provocative words--often captivating, but not often convincing.