Everybody always talks about how great John Stowell is, and I agree. What's great about John is that when he does a duo or group record, everybody else on the project is at the same high level, and I've discovered quite a few good players by listening to his records.
I've also heard greate things about his teaching methods, and he had a hard-to-find series of three videos out years ago, but no books. But now Mel Bay is bringing out this material on DVD (Yes! I can watch it on my Mac!), and they posted an eye-opening lesson on their site, which includes a 15-minute video clip.
The lesson is on substitutions using triads, and it shows how, over a C Major 7 chord, you can play a C, D, E, F or G major triad over the chord, detailing what you will get. For me, it illustrates both the freedom and the possibilities of jazz improvisation. If you know where you are in the tune, you have MANY places to go.
I'll have to try this out. I understand how the D major triad gives you the 9th (D), the #4 (F#) and the 6th (A); but I'm a little fuzzy on why you'd play the E major triad, since you get the 3rd (E), then the #5 (G#) and the 7th (B). I didn't think that the #5 was all that common or desirable over a major chord, and since the iii chord in the key (in C, that's E minor) is such a good choice, why you'd want to play the III (E major) anyway?
"It's just nice to have the variety," Stowell says in the video, and it helps to have some extra "colors in your palette" to play over the Maj 7 chord if it comes up a lot in a tune.
Anyway, the video looks really good, John is VERY clear and methodical, and at $19.95 for the DVD and 40-page book, this is another one on my list to check out.