I do own the book and I'd recommend it. There's not much cocos2D in it (only the bonus Chapter actually contains a cocos2D example) but it does cover a wide range of subjects around game development for the iphone. Each self contained chapter is written by a different game developer and covers a particular aspects of game development.
Of particular note (at the moment as these are the ones I have pored over the most) are;
Chapter 3: Rapid game Development Using (Mostly) Standard C
Chapter 4: Brian Greenstone's Jedi Master List for Game Optimization
Chapter 6: Multiplatform Game development: iPhone Games for Linux and windows
and the bonus Chapter mentioned above. The book has a reasonable number of code examples and these can be seen in the free source download from the site, don't be put off by the lack of source examples for the other free Chapter (chapter 1)
It's not necessarily going to help you build cocos2D applications but it may help you think outside the framework and open up platforms other than the iPhone.