I really like Cathy Toll's views on coaching and especially the respect she shows for teachers in her conversations with them. Her views fall strongly in the "cognitive coaching" camp, which differs somewhat from my approach, but I know I can learn a lot from her. This book includes regular vignettes that allow us to see her in action, and while they're not completely realistic, they come close. Her information on dealing with intimidating or overbearing people in group situations is particularly useful.
We use this in our Administration and Supervision class. Toll is masterful at setting up scenarios and then showing you how to use talking and listening to problem solve effectively together.