I am Studying this book. Guitar Soloing, The contemporary Guide to Improvisation by Gilbert Marlis. The book introduces the Dorian scale intervals and indicates it as the second mode of the major scale. I am good with that. The book also says it will approach the Dorian scale as it's own entity which has it's own set of chords and sounds. This is supposed to let the player become familiar with the sounds and tendencies of the scale/mode. The book says the Dorian scale is a minor tonality and may be used from the root of a minor chord. It also said it (Dorian) should be used when the IV cord in the minor tonality is a major triad or dominate chord. The book then shows a vamp of Cm7 and F7 on a staff with the key signature of Bb. and says I chould use the Dorian scale located at the key center (C in this case) to solo over this vamp. The book indicates the Cm7 as the i chord and the F7 as the IV chord. Here is my problem, Isn't this getting a bit complicated and contorted. What is the value of looking at this as C Dorian instead of Bb major scale with a ii V progression and a tonal center of C. I know I am missing something, what is it? And while I am on the subject, why have a natural minor scale when there is a relative major that works just fine. It looks as if the Natural Minor is discussed only to set the stage for discussing the harmonic and melodic minor scales.