This book explores the meanings of shamanic knowledge and power among the Baniwa, an Arawak-speaking indigenous people of the Northwest Amazon in Brazil, with whom I have worked since 1976. It focuses on the only living jaguar shaman among the Baniwa, Mandu da Silva of the village of Uapui, Aiary River, who has been a shaman for more than sixty-four years. The idea to write his biography came from his daughter, Ercilia, and Mandu gladly obliged. His narrative is the only one on record of a shaman who is today considered by many Baniwa to be a “wise man” (sábio in Portuguese; kanhenkedali in Baniwa), or what is referred to in the anthropology of religion as a prophet. By “prophet,” I mean men and women believed to have the power to communicate constantly with the principal divinities, who advise them of things to come and of the attitude people should take in relation to those forthcoming events. Prophets are recognized by the culture as having the sole legitimate power to announce future events and warn of any imminent dangers.