Designing for the Internet is not what it used to be. In the good old days, Web design was limited to Hypertext Markup Language (HTML), and if designers really wanted to get fancy, they would use Dynamic Hypertext Markup Language (DHTML) for all that dynamic content. Macromedia (now Adobe) changed all that; we started to use Web sites that were designed not only with smoother graphics, but also in a way that provided the most information in the least populated manner. At the same time, users started using the Web for much more than just text and simple pictures. Hence, the programming community had to catch up by incorporating pretty and flashy graphics. Consequently, programmers--who are usually average designers--want all those nice graphics to work with; designers--who are usually average programmers--want the flexibility of associating these nice graphics with real-world data, moving them around to present an attractive and rich user interface (UI) to the end user.

So, what is the need for Flex when we already have Flash? In three words: rich Internet applications (RIAs), which is what this book is all about. The RIAs “often transcend the perceived limitations of the Web browser,” and Flex provides the framework to generate such dynamic and fluid content--not only for the Internet, but also for desktop applications.

But what about ActionScript in Flash? Flex provides hooks into the underlying ActionScript. In Flex, all the aspects of the UI can be represented in Extensible Markup Language (XML) format and compiled into ActionScript.

It’s exciting that one does not have to spend hundreds of dollars on Adobe products to be able to generate nice graphical components for customized applications and Web interfaces. However, the book favors the use of the Flex Builder, Adobe’s Eclipse-based standalone application development environment. Flex Builder costs serious dollars (after 60 days of evaluation); this was disappointing, considering the open-source power that Flex can offer.

The book can be roughly divided into four categories. First, there are five chapters on different aspects of styling--that is, how to make ordinary aspects of UIs, such as buttons and boxes, look pretty. Second, there are three chapters on the components of UIs, such as lists, cursors, and layout. Third, there are three chapters on fancy stuff, such as skinning, animation, filters, and blends. Fourth, there are a few chapters on aspects of the integration of Flex with Flash and with AIR, Adobe’s runtime integration environment.

I am not very clear about the intended audience of this book. For example, the book delves into the XML code for developing the Flex components, without giving any examples of how to compile and observe the results. Hence, it is certainly not for beginners in either Flex or Flex Builder. Also, the book does not take the approach of describing one nontrivial application from beginning to end. It has bits and pieces of example code that describe specific solutions, in specific UI design and presentation situations, but the topics covered are generally of low-level design--for example, how to space the controls, using the tool tip manager. Shouldn’t a nonbeginner be aware of these basic design skills?

Overall, the book is an easy read. Since the code examples are very specific and small, this book can serve as a good desktop reference for Flex designers who are, perhaps, already familiar with Flex Builder and basic Flex compilation and usage. Specifically, the references section provides very useful information for developers.