Book excerpt: In the first book of its kind, John Corbett's A Listener's Guide to Free Improvisation provides a how-to manual for the most extreme example of spontaneous improvising: music with no pre-planned material at all. Drawing on over three decades of writing about, presenting, playing, teaching, and studying freely improvised music, Corbett offers an enriching set of tools that show any curious listener how to really listen, and he encourages them to enjoy the human impulse-- found all around the world-- to make up music on the spot.