This book is short, and clearly written. It is often funny, and is very easy to understand. The author goes into enough detail and gives advice on enough side issues (car aggression, techniques for specific kinds of dogs or owners) that I get the sense that she has worked these principles for a very long time with pretty much every kind of dog out there. In other words, at no point did I think, "but what about my dog, he's different because" without the author addressing the issue a few paragraphs later.
If you want volume for your book-spending money, you may be a little unhappy with how short the book was, but I was relieved by it -- I wanted to finish the book and start applying the training ASAP, so the shorter the better.
The "watch" technique is working for my dog. He's not "cured", but we are having positive events -- I got him to watch me while we were in my truck instead of lunging and barking at a dog that was walking by. He also let a cow (we hike, and ranchers let their cows out in the high country to graze) walk within ten feet of us and did not even bark. He actually stayed calm and kept looking back to me for treats. Maybe he doesn't mind cows (!), but staying that calm near another strange animal is new behavior.
I still expect it to take several months before he lets a dog go by us on the trail without trying to tear it apart, but I am seeing very small results just one week into using the watch command. Like the author suggests, we are working with easy to moderate situations, and just getting those down before we move on to high stress situations.
I have worked with 2 different $80 an hour dog trainers on this problem with my dog, and while they did teach me helpful things, I think I've gotten more useful information out of this book. If you can't afford a trainer, and you feel like you can't go another day with your dog acting like a maniac, definitely give this book a try.