Rating: 

However there are some flaws. As other people mentioned it, this book suffers lots

of typos, which are not just errors in typed characters but also the explanation.

Unlike other programming environment, Cocoa programming with Interface Builder uses mouse-work like drag-and-drop for "programming" not just editing. What I mean

is to connect outlet to some classes represented as graphical element in the Interface Builder. So, if there is some "missing" sentence, then the code is not going to work, and it's hard to find what error you have. Because of this, you can't use "diff" for finding errors with the code examples downloadable from the Oreilly's web site some times.

So, how much writing errors in this book is very important to gauge how well written this book is. So, this books should be revised seriously.

Second, multiprocessing sample doesn't seem like serious multiprocessing example,

although it's good example. There is no example which uses "fork" and "join" seriously. Whether they are wrapped or not.