I really enjoyed this great comprehensive book by Mari Hall,who was and may still be, the director of the International Association of Reiki. I enjoyed the historical review of Reiki and also the easy to follow methods of applying this universal life-giving energy method of healing made famous by the Japanese.
I've re-read this book in preparation for giving a Reiki class. It is a full, useful, and user-friendly guide to everything about Reiki. It contains much more info then I could ever impart to a student, thus making it a valuable tool.