Flex has grown from just a way to build Flash apps into a rich ecosystem, and Flex 4 introduces new UI components, better performance monitoring, and speed enhancements to the compiler.
Flex 4 in Action is a comprehensive tutorial that introduces Flex to web designers and developers. It starts with the basics-forms and data - and moves through core concepts like navigation, drag-and-drop, and events. Even if you're new to Flex, this book is all you'll need to make your apps pop using the new Spark components, data services, charting, special effects, and more.