I've trained in martial arts for 13 years and now teach. This book is useful as it covers a variety of vital points throughout different areas of the body to attack as well as the direction of attack. As always, the effects are often exagerated (unless you've spent many years conditioning your body for such strikes and generating sufficient power).
The vital points shown are individual sites (i.e. no set up points or trigger points) with clear physiological effects. Most of them are also well known to those who have studied pressure points to any degree.
I like it because it gives a simple summary of many of the best points to strike. Although it is not comprehensive (and some of my favourite non-lethal ones are not included) it covers a large range of points. The medical waffle is a bit irrelevant and is more about anatomy and not physiological response. Also, the method of striking is not always the way I'd do it and the examples of striking are not the best (two kung-fu people dressed like ninja doing very poor technique).
Buy this: if you are in law enforcement, if you know nothing of pressure points (but train in self-defence or a martial art) and wish to understand simple yet very effective (physiologically) points to attack.
Don't buy this: if you know a lot about pressure point strikes and are looking for something to complement your knowledge (some of the strikes are sub-optimal and although effective, it is simplisitc and doesn't give some of the more interesting points of Dim Mak)