This book has the same problems every book on music seems to have: a lot of "a dominant 7 chord looks like this" and then a big chart of how to reharmonize what with what. Which is to say it's probably really helpful if you have a specific question you want answered, but falls flat on the topic of "how do I learn this stuff?" and "what are the most important pieces here?" As such, I'd say that this book is useless to an amateur, self-taught musician.