This book is based on, and a commentary, on the King of Meditation Sutta. The author doesn't go through the sutta in a linear fashion, but takes it apart and enlightens the reader with an idea or interpretation on that verse. It is a great way to understand the sutta and to gain a grasp of coming up with your own understanding.
At the end of each chapter, the author gives you insight and ways to improve your path as a Buddhist. It is an amazing way to keep you engaged and apply the principles of Buddhist philosophies.
I would recommend this to anyone, no matter if they are a practicing Buddhist or not, or the level they are involved with Buddhist teachings.