The first thing to remember about Step into Xcode is that it's a book about Xcode. Because Xcode is designed around the programmer's workflow, the first half of the book takes you through the typical workflow of designing and implementing a Cocoa application in Objective-C. 
 
Despite the subtitle of the book, Step into Xcode is not a book about Mac OS X development tout court. It is not a book about languages or frameworks: I go into Objective-C deep enough to make the code examples readable. I explain Cocoa enough to make Xcode's and Interface Builder's features for Cocoa meaningful. 

• Are there better books about Cocoa? Certainly: Any book that is about Cocoa is bound to be a better Cocoa book than a book about Xcode.
 

• I don't cover development for Carbon. This is true, but covering frameworks is not what I set out to do -- I don't cover Cocoa (well) either. The narrative in Part 1 was supposed to demonstrate how Xcode is used; A parallel demonstration for Carbon would be pointless and redundant.
 

• I don't cover the use of Interface Builder for Carbon applications. This is a fair criticism. All I can say is that without a Carbon project to use the resulting NIB, it was hard to fit an example of a Carbon NIB into my narrative.
 

• I don't cover C++. Again, my aim was to explain Xcode, not languages. Also, some of Xcode's features — the class modeler most notably — aren't quite ready for C++. On the one hand, I'd have to discuss those weaknesses (and I think I dissed Xcode enough in the Codewarrior chapter); on the other, I'd expect the weaknesses to be the first things fixed in new versions, and I was reluctant to include material that would go stale during the lifetime of the book.
 

• I don't cover Java. As with Carbon, a parallel narrative focused on Java would be mostly redundant (for my purposes). Also, Xcode is frankly a mediocre tool for Java development. Use Eclipse instead.