On the negative side, Walsh has a poor opinion of anthropologists, yet he relies heavily on the work of anthropologists who are marginal in the anthropological community. Many of his resources are outdated. The book is not very deep, yet this makes it accessible to just about anyone. It doesn't "feel" like it's written by an M.D./Ph.D. -- Walsh slips easily into New Age thinking -- yet, again, it's accessible.
This quasi-scientific book is good for anyone interested in knowing more about the psychology of shamanism. It's well-written, the chapters are short, and it's easy to understand.