I'll be talking about this book from personal experience, not from any scientific backed data
I bought this book a year ago when I was a new guy to the gym not knowing what to do and afraid of what to try. The title is very misleading because the book actually concentrates on your core, not your abs. This means your quads, hamstrings, gluts, lower abs, upper abs, chest, and back. The secondary muscles are improved and/or maintained are the shoulders, biceps, triceps.
So this book actually lays the basic foundation for building a superior core, that your entire body will actually start to feel very springy in normal everyday activities (like standing up from a chair, getting out of bed, heavy tvs, etc.) The attempt is to work all your stabilizing muscles to get the support needed for your normal workout routine.
Before I tried the shockwave 1.4 protocol, I went through 3 cycles (1 cycle = 3 stage = 6 months); this was before finding out about CNS and CBL. Before that, my legs and upper body were lacking quite a bit. Seriously I was struggling on 145 lb bench press (now I use that weight as a warm up). After reading the shockwave protocol e-book, I did see that the core wednesdays is a bit lacking, and I change it up by adding a few interesting workouts in there specifically targeting my lower/upper/full abs. So due to my solid core foundation, most of the exercises in shockwave protocol made me feel great. I was able to get through solid effort pain free. In addition, in my first week I've lifted weights I never could have lifted prior to the NROL for Abs.
I'd actually recommend this book as a positive supplement to an old work routine or if you just want to get introduced to the exercises you're afraid of, or exchange a few of the exercises from the shockwave to ones you learned in the book.
So basically, if your squats or deadlifts are a bit lacking or if your bench press isn't improving then it's perhaps due to a weak core and weak posture.
The other reason why I support this book in your library is because they offer exercises safe for the back. So if you are in rehabilitation, or if it's been a while since you been in the gym, a few of the work outs lined up provide solid routine.
Some of the exercises are a bit weird, like an off loading squat or the alligator drag or the turkish get up, but they make heavy uses of plank workouts piquing the interest of gym onlookers.
Now, some of the weird things you might notice from the book is the lack of bicep exercises. I was kind of skeptic at first, but in 3 months my biceps have actually improved naturally due to the workout of the exercises explained in the book. There is no ab crunches or sit-ups mainly because of the stress on the lower back. There is also no ab-roller because the routine is limiting (according to the author). All the exercises gives you a huge range of variety and advancements.
If anyone has this book already, I'd love to hear from feedback. If you don't and have questions, feel free to ask.
Downsides: This is not a fat burning book or a building mass book. I do have a critique of the authors, in that I've seen videos and pictures of them, and although they are a bit knowledgeable about routine, they don't look fit themselves; which surprises me since people who went through the book have seen extra improvement and support. Dieting isn't mentioned often neither is HIIT; and the fact that this book is not suppose to be a main routine like the shockwave 1.4, just a book that supports it. I suppose ironically people on CNS or CBL would be able to get better results than the authors themselves.