This book has gone under the radar based upon its title. It truly does not explain what this book can teach you.
Basically it teaches the basic Flash user that you can extend what Flash normally does for you in its normal authoring environment. Like create new drawing tools, create commands that perform complex real-time tasks instantly (similiar to custom macros), create custom user interfaces, add timeline effects (scripted tweens) to any object, and create scripted behaviors (prebuilt code components) to help almost automate your Flash development.
If your an exisiting Flash developer who knows how code with ActionScript and needs a way to streamline your development environment and development time, this is a book you shouldn't pass up.