To me, Frank’s series about the General Tonal Center Concept is an excellent tool. I never could figure that Wes Montgomery, Barney Kessel or none of the great players could improvise wondering "now, which mode shall I play over this chord". Frank goes straight to the point where you can create your own lines,free enough to become yourself. The General Tonal Center Concept brings you from a very basic to a very sophisticated level of improvisation where you can play using all the altered tones you could dream of, BUT never losing your own voice. Frank shows many great tunes to illustrate his concept and answers very kindly and clearly to the questions asked during the class. SIMPLY ESSENTIAL !