After nineteen years of kidding myself that I was an okay guitar player, I splashed out on 'The Jazz Theory Book' in the hope that if I read and absorbed it, I might finally be able to comp along with my Bud Powell CDs. The first thing I learned was that, by the time I finish this book, I will be able to have a go. The second thing I learned is that it will take me years to finish this book. Levine is a gifted teacher; he introduces each new thing step by step, working up from simple scales (even I was familiar with the stuff in the first 50 pages) to more complex ones, reharmonisation, modal playing, altered chords and all the other stuff that people spend a lifetime getting to know. At each step, there are none of the sudden leaps in assumed knowledge that I've found in other instruction books. All the way along he demonstrates how what appears to be an unclimbable mountain of knowledge is in fact just a really big hill, by showing how different areas of the music are in fact based on similar principles.