Yan Gaofei, with Jude Smallwood, has written a comprehensive compendium that contains practical guidance and a lot of background information in order to get closer to the understanding and experience of Chi. The book covers most of the content, which Gaofei Yan has passed during his classes and seminars. Explanatory illustrations and interesting imagery (eg "young Yan" page 157) complement the informative work. I like the "Internal Journey Map," which is inserted at the beginning of each chapter and gives the reader a good orientation. The book cannot replace the personal guidance of the teacher, but it helps students to understand what they have learned and experienced. Great work!