Seeing, knowing, and power, these are the three key words that guide the different phases of learning and shamanic practice among the Yagua, an indigenous Amazon society living in the borders of Peru and Colombia. Like many other peoples in this region of the world, the Yagua does not think about the relations to nature and entities (spirits) that populate it in terms of breaking, but continuity. The essential shamanic function will therefore be to ensure the proper management of these relations from a strong idea: the belief that spirits not only hold or control all knowledge about nature, but also have a clean spiritual principle, making communication possible with them. It is at the exploration of this open thought about the experience of the author that he invites us through a long experience shared daily with yagua Shamans. This book aims to contribute closely to the effort to upgrade shamanism at a time when, probably victim of his recent success in the West, he is prey to the most diverse drift and interpretations. Far from being a legacy of the past or the archaic and fossilized reflection of a world that has never disappeared, far from the enchanted dream of a Western who is seeking spirituality, Shahamanism is more likely to be a phenomenon of current history and a factor of ethnic, social and cultural identity of the world's most important native peoples. See, knowledge, power marks a significant step forward in the studies on shamanism. In this new edition, the author shows that Shamanism has not only lost nothing of its vitality in the Yagua over the past 20 years but has become more than ever a dynamic element of becoming an American society.