Satipatthana: The Direct Path to Realization
There are several good books on The Four Foundations of Mindfulness but Analayo's recent work is among the most thoroughly rendered. The form of meditation discussed in this work is generally known these days as 'mindfulness' meditation, or in other circles as 'vipassana' (often translated 'Insight' meditation). Analayo has written a wonderful treatise on this ancient form of Buddhist (or perhaps pre-Buddhist, as you'll see) form of practice.
This book is highly recommended to novices and advanced meditator.