This is a book that reduces the complexity of jazz improvisation for beginning students. The method only requires students to learn how to play major scales and blues scales over standards and in that regard it is successful. However, when I used the method with my guitar students their knowledge of major scales was not proficient enough to use the book effectively. That was discouraging and I ended up using a different method of "Pentatonic Scales With Added Notes" which is a method detailed well in the TrueFire internet course "Soul Jazz Survival Guide" by Fareed Haque. Also, when I teach jazz combos with other instruments such as saxophone, trumpet and keyboard I tend to use the method outlined by Jerry Coker in Jerry Coker's Complete Method for Improvisation For All Instruments which uses modes, digital patterns and fast moving changes from the beginning. However, this is intense and students who are not dedicated to practicing will be overwhelmed or discouraged. In contrast Cutting The Changes: Jazz Improvisation Via Key Centers is purposefully simple so the student is not overburdened by the material. Switching from scale to scale is just one step beyond playing over "one chord drones" where you use one scale/mode when improvising over a single chord. In any case this book has an interesting approach that I can use in addition to other methods. Also, Garcia has another book on the CD-ROM that comes with this book for teachers to see what he is thinking in terms of "cutting the changes" relating to traditional jazz theory.