This is the 4th edition of the world's bestselling book on Objective-C programming, fully updated to cover Xcode 4.2 and Automatic Reference Counting (ARC). Programming in Objective-C is a concise, carefully written tutorial on the basics of Objective-C and object-oriented programming for Apple's iOS and Mac platforms. The book makes no assumptions about prior experience with object-oriented programming languages or with the C language (which Objective-C is based upon). Because of this, both beginners and experienced programmers alike can use this book to quickly and effectively learn the fundamentals of Objective-C. Readers can also learn the concepts of object-oriented programming without having to first learn all of the intricacies of the underlying C programming language. This unique approach to learning, combined with many small program examples and exercises at the end of each chapter, makes Programming in Objective-C ideally suited for either classroom use or self-study. This edition has been fully updated for the significant changes in iOS 5 and Xcode 4.2. One of the biggest changes is Automatic Reference Counting (ARC). This edition gives detailed coverage of how to use ARC to improve and simplify memory management in Objective-C programs.