Psychologist Villoldo (Millennium: Glimpses into the 21st Century, ed. with Ken Dychtwald, 1981) teams up here with San Francisco playwright Jendresen to write an overripe and murky account of Villoldo's journeys to Peru to sample a mind-altering drug--a close encounter with the powers of the mind that led him to a legendary shaman who taught him the ways of the mystic ""Medicine Wheel."" In 1973, inspired by a friend in medical school, young Villoldo travels to Peru to find a psychoactive drag called ayahuasca--""the vine of death."" An eccentric old Indian professor at a rustic university directs him to an Indian who is an expert on the drug. After a terrifying experience on the drug, Villoldo straggles back to the professor only to find that he is leaving for a two-week ""walking tour"" of the remote highlands. Accompanying the old man, the young psychologist soon discovers that the professor is really Don Jicaram, a shaman of legendary power. In short order, Don Jicaram explains the four cardinal points of the sacred Medicine Wheel: The West, the direction associated with the Vine of Death, symbolizes the psychological struggle to overcome the fear of death; the South is associated with confronting the paralyzing influences of the past; the North represents embracing the pacifying influence of the feminine; and the East is the direction of the visionary who has overcome ego. The wise old shaman designs drug-fueled experiences in exotic settings like Machu Pichu to demonstrate the power of some of those directions. Some years later, Villoldo jots down this brainstorm: ""Think of Medicine Wheel as a neurological map for overriding the four operative programs of the limbic brain--fear, feeding, fighting, and sex."" But Villoldo, who went on to found a ""brain/body interface playpen"" at San Francisco State Univ., never manages to explain clearly--much less prove--what he says. Pale shades of Castaneda, with some convincing and earnest detail clawed and trampled by a menagerie of phantom eagles and other shamanistic beasts.