This is a good book for elbow and insert strikes.eg.. what to do on a missed jab or hook. For the price I thought it was worth it but their is probably nothing new for intermidiate or advanced strikers in MMA.
I must confess right away that I am very impressed with everything I've ever read or watched on fighting that Mark Hatmaker has put out. This book is no exception. First off, Mark is an excellent writer/teacher. The book is very well structured and clearly laid out so that the concepts presented flow together seamlessly and build layer upon layer. The interested reader will find a ton of useful offensive and defensive techniques (and some that are both - e.g., "pickoffs" wherein a defensive technique is used to inflict pain and damage - what the Filipino martial arts refer to as 'defanging the snake') that can be put into practice. Much of it is essentially derived from what is termed 'dirty boxing' because it includes things that were made illegal by the Queensbury boxing rules for pure sport boxing application. This is NOT a book about the sport of boxing (or kickboxing, for that matter), although a sport boxer who sought to bend the rules when possible could certainly derive benefit. However, the information is presented from the more familiar/traditional boxing framework. Beyond just specifying the creative use of more traditional tools (jab, cross, hook, uppercut) and less traditional tools (elbows, knees, gouges, stomps, etc.), Hatmaker lays out the concepts such that the reader is encouraged to be a bit innovative and improvisational in the application of the specific strikes and patterns/combinations - which is what you need to do anyway when in a real fight or match. This work is not just a re-hash of Muay Thai handwork (e.g., using fist and elbows), either. There is a lot of stuff on 'how' you use your fist, elbow, forearm, etc. to create specific strike variations. If you think about it (and Mark mentions this in his video series on the subject - see below), adding in the less traditional boxing tools with the more traditional creates a very large number of possibilities.
I would suggest the person to whom this type of approach seems logical/interesting look at the practice of Panantukan from the Filipino martial arts - some overlap with the 'dirty boxing' or 'old style boxing' framework, but relatively more in terms of grabbing and controlling your opponent and using imbalance and directional force to augment the power of strikes. There is some information in the book on using the legs for strikes (and as the target for strikes on your opponent), but its emphasis is much less than on hand strikes. Hatmaker is clear on this in the text, and his rationale is pretty solid, I think. I would suggest that the person interested in augmenting this text with other information on legwork search on information on Dumog (learn especially about foot trapping!) and perhaps Pananjakman/Sikarat from the Filipino martial arts, which, in my opinion, blends well with the hand and upperbody work presented here.
Hatmaker has two separate video series that each contains two VHS tapes: "Extreme Boxing" and "Illegal Boxing". Between the two videos, much of what is in the book is demonstrated and elaborated upon, so these are great supplements/companions to the book. The lowest price I found for these tapes was actually on Mark Hatmaker's own website (search for 'extreme self protection' and 'Mark Hatmaker' and you will find it).
Finally, the book is an outstanding value. You get a ton of useful information for the money, and it is worth a price much higher than is charged. Although I didn't check specificaly, I would imagine one could find a used copy for very little (that is, if someone were willing to sell such a great book!).
I do not know Mark personally, but my familiarity with his work shows me that he is one of the very best teachers on the fighting arts out there. Great stuff - check it out for yourself.