To me, 4 stars means "good" - "better than average" but not "excellent." Although I'm a little tired of books which review the "this is how this piece moves," this book only give a token nod to piece movement. It focuses mainly on four basic concepts: force, time, space and pawn structure. If you don't understand why these four topics are critical to your basic play, this book is for you. This book, as does the entire series, has quizzes throughout the chapters and tests at the end of each chapter. These help make sure you understood what the chapters were about. The last real chapter covers annotated games that nicely demonstrate the principles. Personally, I enjoyed the history section in the beginning. I had grown a little tired of "the queen wasn't always this powerful" descriptions in most books and I finally know when the pieces' powers changed and what they changed from... nice perk.