This book is about bullies - the author calls them invalidators. He talks, generally, about those who are compelled to be nasty to others. He also talks about those who intimidate their significant others in relationships (when you're under the same roof with a bully).
I found it interesting, and refer to it when I've been victimized, but I found it slightly lacking. My bullies were schoolyard peers, as well as adult bullies -- co-workers, neighbors, nasty drivers, etc. He didn't cover those much or at all. (I emailed him about that. I suspect his next book will cover them) I do recommend it, anyway. The basic psychology is the same for all abusers -- they need to put down others to make themselves feel superior. It's not about YOU, it's about THEM.