The author shares this book as a support for his more person to person teaching. He has created Tai Chi Chih which is a simplified form of Chi Kung that is focused on energy movement. I think the improvements to Chi Kung in this focus are helpful. This book is interesting because it describes a lot of the author's experiments in meditation in his life. I was particularly interested in his generation of Tumo heat. He does not use the traditional method, but his own hybrid method of creating the heat and did a good job of it. From my own experience, though, I would recommend those interested in long term Tumo practice get an Empowerment to Vajra Yogini so that the energies can be regulated by the diety and make the practice a little safer. The author has another book that goes into the Chi Kung system he has created. It is only really mentioned here, because some of the experiments use it as a foundation for getting the chi circulated through the meridians first (a good idea). The warnings he has about the dangers of meditation I suspect relate to somethings he has met with his students. I personally feel meditation is safer than the impression I get from his writings, but the warnings may still be worth sharing. These precautions may be more important to follow if you do not gain the benefit of an empowerment. I gave the book four stars rather than five because it is a little loose and incomplete, it would not be enough of a meditation book by itself, but has some useful notes for those already familiar.