Whilst living amongst Peruvian Indians, anthropologist Jeremy Narby learned of their phenomenal knowledge of plants and biochemical interactions, gained under the influence of the hallucinogen ayahuasca. Despite his initial scepticism, Narby found himself engaged in an increasingly obsessive quest. He researched cutting-edge scholarship in subjects as diverse as molecular biology, shamanism, neurology and mytholohu, which led him inexorably to the conclusion that the Indians' claims were literally true: to a consciousness prepared with drugs, biochemical knowledge could indeed be transmitted,...