I'm not a big fan of game guides in general because games typically don't require them. I have beaten all the games i've purchased just by playing and figuring things out. The reason i wanted a guide for Arkham City is because the game is huge. I knew that if i simply played and tried to figure things out on my own, i would never get to experience the entire game.
For example, after saving Catwoman from Two-face, i left the building through the nearest door and continued on my way. After i bought the book, i replayed that scene and it told me to take a different door, head down the stairs where i could find Calendar Man. Without the book, i never would have thought to take a different door and i never would have found Calendar Man(which also has an associated trophy). This little tidbit isn't needed to beat the game, but it does allow me to experience more of the game. And for such a huge game, i don't want to miss anything.
The book is well laid out. It gives you some good tips on combat, and it also suggests which upgrades you should get first. This little tip alone helped me to increase my xp points tremendously during battle. Then it goes through a complete walk-through of the game. Finally, it explains how to find all of the Riddler trophies.
The only downside so far is that it doesn't tell you which buttons specifically to press. For example, instead of stating "press the square button," it'll say "press the punching button." Instead of saying "press the triangle button," it'll say press the counter button. Or press the glide button, press the crouch button, etc. Without having the little manual that came with the game, you won't know which button the guide is referring to. The guide states the reason they left out the specific buttons is because xbox and PS3 have different buttons. So what? Just include both options like all other manuals do.
I didn't want to drop my rating for that negative aspect alone. The guide helps you get your money's worth out of the game and will help you see things you might not have known were there.