This is definitely a unique book in my opinion, because it presents a new way seeing the modes of the major scale in terms of their applications. And it definitely provides knowledge that you can start applying right away (which a very important criterion for me).
The basic idea behind the book is to develop a system for using the structures within the modes of the major scale to solo over all chord types. The authors present a logical way to do that, but this may come as a surprise for players who were previously taught of major scales modes in the old fashioned way, ie: Phyrigian mode works over a minor 7th chord, Locrian works over a m7b5.. Well, NO, this is not entirely true. Actually, in real music, we are hearing such modes being used in different functions all the time..And the authors explain why..
The approach in the book focuses on chord progressions instead of individual chords. This is, in a sense, similar to soloing in key centers. However, while soloing in key centers does not allow you concentrate in essential tones that you should emphasize, the so called "pitch axis" system of the authors does allow you to do that exactly. If you have been wondering how proficient players are able to outline chord changes with a few notes, this book may be what you need. I believe open-minded players, even if they have been taught of the modes in the old fashioned way, can also benefit a lot from this book. The authors use the progressions to well-known jazz standards (in order of increasing difficulty) to apply the ideas presented in the lessons, but I believe musicians dealing with other kinds of music can also benefit from the material if theye are interested in improvisation.
The examples have been notated and tabbed, but the "tetrachords", which are four-note structures used by the authors as the simplest source of linear lines, are notated in standard notation, so some basic sight reading would be helpful.
Last but not least, the authors state that modal improvisation is just one of the ways they teach.. The system taught here is definitely a very good one, but there are other approaches as well. If you are willing to get more into the typical jazz (especially bebop) language where chromaticism plays an important part, you should be aware that this not the focus of this book. For more information on the use of chromaticism and typical bebop lines, I suggest you check out Don Mock's "Target Tones" book. I bought these two books together and they turned out to complement each other in an unexpected way. Sid Jacob's book on "Playing the changes-Guide Tones" and "Jazz Guitar Phrases" book are also highly recommended for that purpose. And finally, if you are interested in the different applications of tetrachords and similar small musical units for jazz guitar, you may also want to check out Andrew Green's "Jazz Guitar Structures"..
To summarize, I believe the information here would be beneficial for all types of guitar players interested in improvisation, and especially in jazz improvisation. I am giving it four stars, because I think the authors' approach could have been expanded for other structures besides the major scale.. But I guess I am a little picky..:)