Flex 3 is the next generation of a technology that revolutionized web applications. It is the next evolutionary step of Flash, which has grown from a web animation medium to a powerful enterprise web design and development platform. With nearly 98% of all web browsers, and a growing number of mobile devices, running Flash Player, a knowledge of Flex is indispensible for any serious web developer. This book will show you how to create powerful rich Internet applications using Flex 3. After learning how to install and becoming familiar with the basics of the Flex Builder 3 software, you will explore in-depth how the Flash scripting language, ActionScript 3.0, interacts with Flex's powerful XML-like design language: MXML. You'll learn how to construct your applications using layout and navigation containers, and how to move between various states using transitions. There is coverage of how best to plan your applications and use the Model-View-Controller pattern to keep various aspects of development separated and ease creation of potentially complicated projects. Rich Internet applications rely on data, and this book shows how to bring data from various sources into your Flex application and check its integrity, and how best to display and interact with it. Going farther, applications built for the Flash platform can now exist and function beyond the traditional confines of the web browser. Adobe AIR allows you to take your applications to the desktop, and this book shows how to reapply your Flex skills to take advantage of this new environment. The Essential Guide to Flex 3 takes you through all the powerful features of Flex using a series of stand-alone, practical exercises. The skills acquired throughout the book are then brought together in the form of a full-featured case study application showcasing essential techniques that can easily be applied to your own Flex applications.