Strong Anywhere is one of the best books on Bodyweight training I have found.
People generally stay away from bodyweight stuff because:
1. They want to look like HUGE bodybuilders
2. Because the bodyweight stuff they know about is either too easy (like basic pushups/situps) or TOO hard (like gymnastics exercises)
Fortunately, for people who fall under #2, Boulter's use of progressions helps you transition from the basic exercises that many people can do towards the intense, ultra-impressive feats normally reserved for gymnasts. By doing easy then basic then intermediate then advanced exercises, one can move towards incredible strength in a logical progression.
For people with the 1st concern:
Boulter's book will make you super powerful and ripped and bigger, but it will probabally not make you as big as a WWE wrestler or a professional bodybuilder. Basically, bodyweight exercises require a high strength:weight ratio. Doing bodywiehgt stuff will make you very strong pound for pound. Additionally, when you are strong pound-for-pound, you will still probabaly be able to bench/squat/press more than many of the biggest guys in your gym, however, you will not be as LARGE as them. If enormous size is what you want, get on Riptoe's starting strength, eat huge amounts of protein, learn how to use creatine. If strength and power is what you want, buy Boulter's book.
I liked it because SImon Boulter does a really good job educating readers about "PROGRESSIONS" which I think are the key to building the strength necessary to do exercises like Levers, Planche, one arm pull ups, one leg squats, etc. He walks you through the exercises and explains how and why to train in particular exercises. Progressions are exercises that fall inbetween the easiest version of an exercise and the most difficult. For instance, for pullups, the easiest exercise is the chin-up. an intermediate exercise is the overhand pullup. harder than that is a wide grip pullup. Harder than that is a clapping pullup. Harder than that is a one arm pullup. Harder than that is one hand pullup. The exercises between the normal chinup and the one arm pullup are the progression exercises.
I liked the book because like Boulter, I'm training hard for Martial Arts and I cannot afford to pay pricy gym memberships (on my student budget). I am finding that in order to get to my maximum strength, I need to refine and strengthen my internal drive, my reslience, and my will power to overcome everything from fatigue to lazyness. Bodyweight training is really useful for me, because it forces me to be honest with myself, and it forces me to constantly ask the question: Am I giving it 110% ? Each time I do a rep, I can tell if I am cheating the rep, if my form is bad, if I am allowing my inner weakness to destroy my workout, and that realization forces me to be more disciplined.