I actually got the book some months ago, but didn’t get the chance to do much more than start it:
Musical Environments: A Manual for Listening, Improvising, and Composing by Richard Vella.
There is no book quite like it – it’s very dense with information and ideas on the creative process. The part that I am now reading and taking notes on (I don’t like to read nonfiction without a pencil in hand) is the “Teaching Strategies for Improvisation.” If you are a kindred soul who reads this column regularly (at least whenever I post something), you should probably run, not walk, to order a copy of this book. Let me share/tease a bit and give you some quotes from this chapter (p. 99):
•a valuable tool for understanding creative and musical thinking.
•can involve working with existing or known structures from which one explores new possibilities, or outcomes.
•is a real-time interaction and involves spontaneous decision-making either consciously or unconsciously.