This book is a general survey of Chan Buddhism written by a respected scholar. It is that simple. It is well written and easy to follow. The author uses images and analogies in relating buddhist teachings, some drawn from the buddhist tradition, others are more secular and contemporary. It is an accessible book for the general reader, though it could also be useful to those more advanced in religious studies.
With all the different "Buddhisms" out there, it was nice to find a book that stuck to the Chinese version of the tradition. So often Chinese, Japanese, and Korean forms of buddhism get lumped together. What I liked most about this book were the distinctions he presented between Indian Buddhism and Chan, making clear how they were different and why they were different. His honest accounting of the influence of Taoism and Chinese culture on a foriegn religious tradition was educating and helpful and answered many growing questions in my own study of this tradition. His discussion of the development of Buddha-nature, interdependence, creativity, and energy work--especially as they are unique to the Chan tradition--provide the reader with a good grounding in the basic teachings of the Chinese tradition. I am, however, still a little fuzzy in my thinking about karma and reincarnation, and perhaps this is an area of the book that is lacking. It is the only criticism I would offer.
If you are looking for an outstanding introduction to this subject, I would recommend this book. The University of Hawai'i Press offers many fine books on this subject. Further reading can be found there.