Introduction Welcome to Objective-C. This book is your guided tour of this exciting language, and it gives you what you need to start working with Objective-C at once. Using Objective-C, you can write professional programs that make use of many object- oriented features--from the basics up to advanced class inheritance and exception (run-time error) handling. Objective-C runs on many different platforms. For the most part, your code should work unchanged on all platforms that Objective-C supports, but where differences in support exist, this book points them out to you. This book starts with the basics and contin- ues on through advanced topics. You'll begin by looking at how to get Objective-C started and how to run basic programs. From there, you'll explore data handling, again start- ing with the basics and moving on through advanced topics. After looking at how to write your own functions, you'll wrap functions and data together into objects--the core of Objective-C programming. And when you start working with object-oriented programming, the lid is off--and we'll push the envelope as far as it can go. i That's the plan, then: to present a guided tour of Objective-C, taking you from the beginning to the most advanced topics. Let's get started with Chapter 1 now. Introduction viii