This series of specially selected quotations was gathered from the first eight books that I wrote about the world of the shamans of ancient Mexico. The quotations were taken directly from the explanations given to me as an anthropologist by my teacher and mentor don Juan Matus, a Yaqui Indian shaman from Mexico. He belonged to a lineage of shamans that traced its origins all the way back to the shamans who lived in Mexico in ancient times. In the most effective manner he could afford, don Juan Matus ushered me into his world, which was, naturally, the world of those shamans of antiquity. Don Juan was, therefore, in a key position. He knew about the existence of another realm of reality, a realm which was neither illusory, nor the product of outbursts of fantasy. For don Juan and the rest of his shaman-companions - there were fifteen of them - the world of the shamans of antiquity was as real and as pragmatic as anything could be. This work started as a very simple attempt to collect a series of vignettes, sayings, and ideas from the lore of those shamans that would be interesting to read and think about. But after the work was in progress, an unforeseeable twist of direction took place: I realized that the quotations by themselves were imbued with an extraordinary impetus. They revealed a covert train of thought that had never been evident to me before. They were pointing out the direction that don Juan's explanations had taken over the thirteen years in which he guided me as an apprentice. (Introduction)