This book covers everything you ever wanted to know(and probably a lot you didn't)about Jazz theory in a mere 50 pages. Intervals, chord structure, modes, substitutions, pentatonic and blues scales, polychords, 5-part harmony: it's all in there. This book is not meant to be a text on improvisation or arranging but merely a reference book. And on that front it succeeds. If Regis called and your friend needed to know how a 13th chord was constructed, you could probably look it up before your 30 seconds ran out. But is it interesting, good, or fun reading? Will it inspire you to pick up your instrument and practice? I don't think so.
I give the book four stars because it does what it sets out to do. It's arranged in an orderly fashion, the chapters cover one thing at a time before moving on, there are quizzes at the end of each chapter to make sure you are getting it. But... I bought the book hoping it would inspire me to delve into some areas I'm weak on and I just can't see it doing that. Plus, it seems a common misconception that all you have to do is learn everything in this book or others like it and you will be the next Charlie Parker. Wrong! Jazz is and always was an imitative art. The theory is used to explain the art but the art didn't come out of the theory. Many of the innovators of jazz did not know half of what's in this book. They learned by listening, assimilating and building upon what came before them. I know 5 times as much about the theory of jazz than my father, yet he can improvise beautiful solos and I run up and down scales.
If you need this book as a reference, fine... plop your money down. I bet it stays on your shelf unless you really need it. But, if you want to improvise , go instead and buy Milt Jackson's CD "Opus De Jazz." You'll learn more from the first song than you can from this or any other book. Plus you'll enjoy it a whole lot more.