This book is pure gold. As the author states quite a few times - most people "do their thing" mostly on intuition. Sometimes it works out, sometimes it's so terrible it actually multiplies your work load.
I like the fact the author takes a step back and doesn't enforce his views and solutions onto the reader but offers self-evalutation, while often stating the obvious and offering a possible way of solving different problems
This book aims for no specific system, as that's something the reader must figure out for him self, however the pointers and hints dropped all along the book should facilitate this task greatly.
All in all, if you struggle as GM or don't feel like everything is going as well as it should, this book is for you.
Even GMs who have been running games for quite a few years might learn something new as this book demands to evalute one-self.
If you feel like you could improve don't look any further. You have arrived at your destination.
[5 of 5 Stars!]