Not many practical manuals are also fun to just read, but this one is - funny, incisive, witty, philosophical and more. It is tremendously useful in many ways. I'm involved in applying impro, but not for Theatre Sports or comedy impro, yet this book is invaluable. My only annoyance is that it should be called Storytelling for Improvisors instead. If you are a storyteller hoping to learn how to improvise stories, this book will not address that directly for you, although if you absorb all the insight you'll get a lot of practical help. Johnstone's comments and analysis are very thought provoking, and reveal a great deal about human nature and the way our minds (and inhibitions) work. Any psychologist could learn a lot here too. If you are after a bumper book of games, go no further - this details a large number, but also with expert advice on how to teach and run the games, including warnings about all the variations that don't work.