Amazon.com description: Product Description: (Guitar Educational). Three books in one! First, a music theory manual that describes the different types of twelve-bar blues forms (slow change, quick change, five chord blues, jazz blues, etc.) and presents them as both chord progressions and structural formulas. Second, an introduction and thorough study of "rhythm" chords the essential three-note voicings that every guitarist must know for accompanying small blues groups to jazzy big bands. Third, a comprehensive series of twelve-bar chord progressions that range from a basic three chord blues to the most advanced, multi-chord jazz arrangements. For all levels, beginners to professionals with large, easy-to-read chord diagrams; most popular major and minor keys; and more!