Wow, such an amazing book. If anyone has read "The Challenge of Fate" before this, then I am sure you noticed how perfectly this book compliments the first. While "Fate" challenged you with groundbreaking theory, this new book actually takes some theory from "Challenge" and spends an entire book, in great detail, explaining how, we must awaken from the world of duality to accomplish something concrete as "health".
This book is almost a scientific approach to Zen Buddhism. I am also reading "Dropping Ashes on the Buddha" and these two books seem to match exactly. While zen attempts to deal with the problem of duality in ritualistic fashion, Dethlefsen and Dahlke go into scientific analogies to show the existence of dualism and it's impact upon our lives. Plus, how to move beyond it. Beyond a world of light/dark, male/female, fast/slow, cold/hot, etc. etc. Basically, this book is a practical application of the fundamental concepts of zen buddhism. The more of our nature we deny, the more builds up on other levels that ultimately spill over onto the physical plane and thus "cause" disease.
This book is a MUST read for anyone who questions exactly "why" things are, the way they are. It will soon become apparent that the answers are correct, we are simply asking the wrong questions.