This book is both ethnography and allegory.

Carlos Castaneda, under the tutelage of Don Juan, takes us through that moment of twilight, through that crack in the universe between daylight and dark into a world not merely other than our own, but of an entirely different order of reality. To reach it he had the aid of mescalito, yerba del cliablo, and humito — peyote, datura, and mushrooms. But this is no mere recounting of hallucinatory experience, for Don Juan's subtle manipulations have guided the traveler while his interpretations give meaning to the events that we, through the sorcerer's apprentice, have the opportunity to experience.

Anthropology has taught us that the world is differently defined in different places. It is not only that people have different customs; it is not only that people believe in different gods and expect different post-mortem fates. It is, rather, that the worlds of different peoples have different shapes. The very metaphysical presuppositions differ: space does not conform to Euclidean geometry, time does not form a continuous unidirectional flow, causation does not conform to Aristotelian logic, man is not differentiated from non-man or life from death, as in our world. We know something of the shape of these other worlds from the logic of native languages and from myths and ceremonies, as recorded by anthropologists. Don Juan has shown us glimpses of the world of Yaqui sorcerer, and because we see it under the influence of hallucinogenic substances, we apprehend it with a reality that is utterly different from those other sources. This is the special virtue of this work.

Castaneda rightly asserts that this world, for all its differences of perception, has its own inner logic. He has tried to explain it from inside, as it were — from within his own rich and intensely personal experiences while under Don Juan's tutelage — rather then to examine it in terms of our logic.