Good post, Bob, and particularly applicable to me. I've been using some of Jamey Aebersold's books, such as "Nothin' But Blues." Sometimes the tempo on the accompanying CD is too fast causing me to concentrate more on keeping up than experimenting with my improv. I should add that I don't do enough improv to have learned it very well. Someone suggested that I study the modes. Sadly, I only made a minimal effort at it as it became more like memorizing for a biology test. I'm sure there are many books on improvization, but, as you aptly point out, it's better to learn by playing. If there was a modes dvd, at a slow tempo, I might do better. Alternatively, maybe I should make up some exercises of my own using BIAB.

Cornet Curmudgeon