Using Xcode 4. Add the coolest features of Xcode 4 to your development workflow, including the newly built-in Interface Builder, the new Version Editor—which works seamlessly with version control systems such as Git and Subversion—and the Clang Static Analyzer.

Classes, Objects, and Methods. Learn the basics of declaring Objective-C classes, implementing their methods, and allocating and initializing instances.

Message Expressions. Objective-C message expression syntax always seems to throw even the most experienced developers the first time around. We’ll show you an easy technique to avoid confusion when reading and writing message expressions.

Message Dispatching. Get a solid understanding of the Objective-C runtime system’s role in dynamic message dispatching, and learn how to leverage Foundation facilities to take advantage of delayed performs, message forwarding, and other powerful techniques.

Value Classes. Learn how to work with Foundation value classes for scalar values, strings, and binary data and how to use utility classes such as NSDateFormatter to convert between objects and their formatted string representations.

Collections. Learn to work with mutable and immutable arrays, dictionaries, and other collection types. Discover how Foundation collections can easily store and retrieve their values on the filesystem, and learn to use utility classes to assist with sorting, filtering, and other common operations.

Error Handling. Apple’s approach to error handling may seem surprising—they discourage using thrown exceptions, and instead suggest using instances of NSError (a simple value class, unrelated to NSException) in most cases. We’ll explain why, and show you how to use the proper techniques.

Managing Memory. Learn the best techniques for working with Objective-C’s reference counting system to manage your program’s memory, including easy-to-follow steps that can help you avoid common pitfalls. And get an overview of how upcoming changes to the LLVM compiler technology could provide additional automation to reduce the amount of memory management-aware code you need to write.

Declared Properties. Understand how to use Objective-C 2.0 property declarations to streamline accessor method declarations and provide additional information, such as memory management semantics, and how to instruct the compiler to synthesize accessor method implementations, and even their underlying instance variables.

Protocols. Get a solid understanding of required and optional protocols, and how Apple uses them to support important Cocoa touch design patterns, such as Delegation. Learn some of the more commonly used protocols in Foundation, and some potential pitfalls—for example, why it’s not always safe to send an object a copy message.

Categories. Learn how to add custom methods to existing classes to extend their behavior, as well as how you can use categories to streamline your codebase.