I teach meditation and have meditated for 25 years, but I still found some new perspectives and exercises in here that I think are very valuable. It's a short book, focusing on three components of any meditation posture - relaxation, alignment, and resilience. It connects each of these to states of mind, for example, exploring the parts of our body that tense when our mind is busy, and the ways correct alignment aids a natural relaxation. The premise is really that by working with these three aspects, one will discover a natural state where all 3 are balanced, and in this state, the mind is also balanced. He also discusses phases of meditation, and how as new things surface during our meditations we will see a reaction in our body. He offers several exercises for working with these themes.
The book does not give detailed guidance on specific meditation postures from different traditions, i.e. lotus vs. zazen, etc., or guidance on meditation techniques. Instead, it is really focused on ways to discover these three components of relaxation, alignment and resilience in any meditation posture, and on how to use this in tandem with working with the mind. The book also does not put forth a particular spiritual perspective, although I would say it is more Buddhist in its perspective than any other tradition. So for beginning meditaters, this is really a book to be used along with formal meditation instruction or another book on the subject. But it is a book that I think anyone meditating within any tradition will find something to appreciate and use.