This work explores the teachings and philosophy of Carlos Castaneda, focusing on the concept of the 'nagual'—a term from Mesoamerican shamanism referring to an unseen force or spiritual guide. Written by Lucien Renart, the book delves into Castaneda's ethnographic accounts of his apprenticeship under Don Juan Matus, examining themes of perception, consciousness, and alternate realities. It serves as both an introduction and critical reflection on Castaneda’s controversial legacy within anthropology and spiritual literature.