Adobe’s Flex 3 framework, for ‘rich internet applications’ is becoming increasingly important for developing both Web-based and (when using the new AIR runtime) desktop applications. In order to master Flex you will need to be comfortable with quite a range of cooperating technologies including the ActionScript 3 programming language, the MXML formatting language, Adobe’s Flash graphics and the huge code library comprising the Flex and AIR frameworks.
The Essential Guide To Flex 3 covers the basic features of all of the above. It also includes a simple guide to using Adobe’s Flex IDE, Flex Builder 3, and designing applications with the various ‘containers’ and controls installed into the Flex Builder toolbox. It has chapters on XML processing, formatting and cascading style sheets, printing, charting and connecting to a data source (the assumption is that this will be ColdFusion though brief mention is given to alternatives).
This book provides an accessible, easy introduction to Flex development, including a short but useful chapter on AIR. It does not go into great depth, however, so if you are new to ActionScript and the Flex framework, you will doubtless need either to buy another, more advanced, book after this one or do what I did: read the compendious PDF documentation provided by Adobe with the Flex SDK.
So, in summary, this is a good ‘first book’ for the Flex novice - but it only covers the basics.