The idea that and may be employed by us to uncover information, to heal the sick or injured, and to punish or to maim others is something that boggles a Western mind. Perhaps even more perplexing is the fact that shamanism is the oldest known form of organized religion, and that there exis~s a large body of evidence that testifies to the power and reality of the spirit world, such as those accounts given in William K. Powers' Yuwipi, John G. Neihardt's Black Elk Speaks, and Mircea Eliade's Shamanism. Perhaps it is this dilemma, that so many people have practiced shamanism for so many years and have amassed definite proof of its inherent healing power, that leaves Western minds searching for a plausible explanation that satisfies their scientific curiosity. It is not the goal of this paper, however, to support or to discredit the evidence suggesting the existence of the spirit plane. That task can only be left to individual experience. Rather, this paper will demonstrate that several aspects of the shamanic world may be explained in biochemical and psychological terms, while recognizing that there are many other aspects which cannot be, or at least not yet.