I read Castaneda many years ago as part of the classic adolescent experiences of that era when I was a teenager. I would have considered the practice closed if it weren't for the reading group that I coordinate on behalf of the library of my country. In short, one evening one of the participants, who had the burden of choosing the next book to read, said that she didn't have a title in mind but a topic, namely certain forms of alternative spirituality, like those that Coelho or Redfield talk about. Since neither of the two would exist without Castaneda, I proposed the reading, especially for the book in question, which presents the anthropologist's first approach to shamanism and alternative spirituality.
The book has two major weaknesses, one related to the writing and the other related to the content.
The writing suffers from the fact that the book was born as a report of a scientific experience and is practically the material for Castaneda's anthropology thesis. This makes the reading difficult due to the categorizations and the note-taking style.
The other limitation is related to the content. Castaneda was an apprentice of the shaman don Juan, who embarked on a journey with him, mediated by the use of hallucinogenic plants, to transform him into a man of knowledge. But Castaneda gave up the apprenticeship, stopped by what don Juan had described to him as the first enemy of the man of knowledge, namely fear. Therefore, his experience is incomplete and lacking, and in large part not understood. And Castaneda describes this incomplete experience, and this pretends to be the basis of an understanding of shamanic spirituality. However, the feeling when reading don Juan's teachings is that this knowledge is reserved, that is, that the initiate should not talk about it. Therefore, Castaneda shows himself, precisely because he talks about it, as an incomplete adept, not entitled to describe this experience, and this affects the entire construction that has been made on all of this.