This book is an introductory guide, apparently aimed at the beginner and intermediate guitar player. Along with a series of YouTube videos, it covers a variety of chords, chord progressions ( jazz, blues, rockabilly, rock ) and some theory. Unfortunately, it assumes a moderate amount of prior knowledge, not really explaining the theory all that well. This serves as a good primer for the returning musician, but doesn't discuss musical theory in sufficient detail for the beginner.
The book's formatting is strange - it takes up a small amount of the page, leaving a lot of whitespace. The text is therefore a little small in places. Despite this, the diagrams are clear and informative.
Overall, I wouldn't recommend this as an introductory text, but rather, as something to fall back on or complement a more in-depth book.