I want to let other readers know what kind of book this is and if it may be useful to you. One reviewer said "Not conducive to insight. Utility is questionable. Book is literally a catalog of definitions.". While it's true that the book is for a good part a collection of concepts and definitions, these are actually essential and fundamental in practices that have as goal to recollect and observe one's mind, such as LoRig. In oder to observe and later overcome your daily actions, habits and other mental activities, you need to know them first, get familiar with how they arise, what are their roots, how do they function and what are their results. This book provides a map or user guide to the mind and its factors, which utility is invaluable if you see yourself repeating the same habitual patterns over and over, and you're into the journey of discovering your own mind.
On the other hand, I believe this book alone it may be of little help to persons who have no received further instructions on these topics. So consider buying it only if you have received oral instructions on buddhist mind training and psychology.