I bought this book based on enjoying this genetleman's website, found here: http://www.functionalselfdefense.org/
This is quite a good book. I am not sure I have seen a self-defense book before that is this general and comprehensive, but manages to keep it simple, and not go off on tangents, as well as teaching some stuff that one could immediately implement in a class or with a training partner.
The first part of the book is stuff that is likely quite familiar to most of this forum, awareness, de-escalation, victim profile, other things that many other authors have covered in more detail - as Mr. Erath readily admits and gives credit for. However, the content is layed out in such a way that it is easy to visualize using for a class, which I appreciated. I have been reading on self defense and including in my Karate teaching for years, but often struggle with structured presentation. Mr. Erath's presentation of this stuff in the book is quite nice, very useable, and I will probably directly use it for classes in the future.
After the non-physical aspects of self defense, Mr. Erath goes into some of his own concepts, the "Covered blast" and the "MMA Base". The MMA Base is training and techniques drawn primarily from Boxing, Muay Thai and Wrestling. These are presented reasonably well in photographs, technique descriptions, and recommendations for simple drills. I should also note that almost all the content in the book is stylistically neutral. Mr. Erath has 20 + years in the martial arts, has trained in a number of different things, and created a very nice synthesis of practical approaches that can be used by almost any style.
His "covered blast" concept is basically the same as Rory MIller's "golden technique" - an approach that insists that you combine attack, defense, positioning and follow up. Nothing earth shattering, but quite good policy that often gets overlooked when training specific techniques.
Following the MMA Base Mr. Erath explains how applying the MMA Base approaches to self defense neccessitates some changes to technique (eg open hands for some boxing punches, etc.), and also introduces a few new concepts and controls that I would suspect come from his Karate and Filipino martial arts experience. At any rate, none of it will be unfamiliar to applied Karate people. Here you will some familiar clinch positions, the use of shuto-uchi, and other "traditional" techniques.
The strength of the book is how it all comes together. You could take the book and simply go through it piece by piece in say an applied Karate class environment, and you would be benefit greatly I imagine. I found that some of his drilling recommendations filled in some holes i'd be concerned with in my own class. Whenver things start back up again, I will be implementing some his ideas.
If you are looking for a book to kind of make the rubber meet the road in your classes with regard to self defense, this book would be a good choice. It is very easy to read, well laid out, and full of excellent information. As I mentioned, it is also fairly neutral stylistically, and completely absent of the usual tribalism sometimes seen in these sorts of books. Throughout the book he stays faithful to practical self defense material, and gives a ton of good training advice.
All in all, highly recommended.