This book is clearly aimed at people who have progressed well beyond the beginner level meditation. Therefore, if the reader is not so experienced or not curious enough, he or she may find this "boring " or Useless" otherwise this is a truly accurate and rare book.
For me this is an unimaginably 100% exact book I wanted. I began meditation without seriously reading any books. But I knew I got to watch my breath and eventually to be locked in to it in order to experience something. I tried very hard but I could not do that. Later I discovered that Metta meditation helps to concentrate, and I tried that and then continued in mindfulness meditation.
One day it happened to me, suddenly felt that I just immersed into something I never experienced before, but continued some days without knowing what exactly it is (I had relatively lesser knowledge in Jhnas and deeper experiences)
Then, I watched this video series: http://www.youtube.com/watch?v=7X4o1Q2QP94 and discovered that I have experienced a Jhana. I was really happy and I kept doing this regularly and I felt that I was becoming more aware and progressing on this.
Then this book came across me, and I started to read it I could not believe my eyes, every word and every step it explained is exactly as I have experienced. I felt so grateful to this monk for writing this book. With this I discovered that I have almost gone beyond 2nd Jhana.
This book has explained all accurately up to where I am now, therefore I can safely assume that rest of it accurate too. If you go beyond basics, this is a wonderful companion. I think this book assumes that you already know about mindfulness meditation and have some knowledge in Buddhism.