It seems mostly common sense (something I feel I'm running low on at the moment!) and focusses on praising any behaviour that isn't bad, and uses token economy reward systems.
I hate parenting books usually, but I'm really struggling with DS1, who has just turned 3. We have a new baby and recently moved house (not area) and I know this has had an impact on his behaviour and the way he feels. 
He fights me on so many things (normal for 3, with or without a new baby, I'm sure) and just getting out of the house to something he allegedly likes doing can be a nightmare - he's fixated on playing with his bloody trains all the time. And he starts preschool on monday. I'm dreading it - going on episodes from the past couple of weeks, it's entirely possible that he'll refuse to enter the building! I'll have DS2 strapped to me, so won't be able to manhandle DS1 - nor should I, if I want him to enjoy preschool. 
Has anyone had any luck with this book? Or can you offer me any glimmers of light? DS1 used to be a friendly, happy, amenable boy and now he's so difficult. I can see why he's like this now, but it's so hard to get through to him, especially now he's developed 'selective deafness' when DH or I ask him for a response, or to do something he doesn't want to do!