One big observation: this book isn't for the novice. If you don't know how to program already skip this one and go to the next one. If you are learning and you feel comfortable with your c++ then go for it. If you have previously worked with CryEngine and you already know how to do a few things but want to increase your knowledge this is a great choice.
The part i liked the most is how it begins by actually explaining the pipeline and teaches the architecture required for a good development environment. The book talks about automatization, build scripts, overnight builds and so on. This is both a book about a game engine as it is a book about being a good organized developer.
The book then dives into how to work with CryEngine, i found it to be an interesting way since you have to create action maps in xml files for the different actions and then reference them in c++. The engine even has a Lua scripting functionality. I won't go very deep but this book covers a lot (different type of controllers, how to deal with dlc, complex logic, bones and animations,...) and i can't recommend it enough if you want to build games, specially with the cryengine. About the engine i have to say that even though there are some free alternatives like blender or unity3d if you have the money to pay for the subscription go for it or just try out the free version.