Get a solid grounding in the fundamentals of Cocoa Touch, and avoid problems during iPhone and iPad app development. With this revised and expanded edition, you’ll dig into Cocoa and learn how to work effectively with Objective-C and Xcode. This book covers iOS 5 and Xcode 4.3 in a rigorous, orderly fashion—ideal whether you’re approaching iOS for the first time or need a reference to bolster existing skills. Many discussions have been expanded or improved. All code examples have been revised, and many new code examples have been added.
So far it's really helpful. It's the second iOS book I got. The first one jumped way to fast into the code with little or no real explanation. This book begins explaining the basics and makes consistent notes about common pitfalls.
I liked the overview of the role of the view controllers and the summary of the life-cycle... clear and succinct. The underlying example of his Latin flashcards app is not for me a template for how to best deal with the case of n peer views in an app, as it would lead to some avoidable complications.
The overview of the language however is really just that... a VERY light summary. Someone serious about objective-c would have to read something else to supplement it.