This book reads like a scientific review article albeit one of 638 pages! The book is not recommended for those wanting a quick introduction into the field of entheogenics. One should expect complete pages filled with botanical names and complex chemical names. For those used to reading scientific literature here finally is a book that takes the well informed reader seriously. Ott also includes results of several very informative self-experiments and has an opinion on the whole issue of entheogenic use that deserves to become widely held.