This is a four-day, hands-on introduction to developing rich Internet applications (RIAs) for the Adobe Flash Platform using the Apache Flex 4.x framework. Late in 2011, Adobe donated the Adobe Flex SDK to the Apache Foundation. It is currently under incubation as Apache Flex. Now, the SDK is truly open source with development driven by community members in a meritocracy. The official Adobe Flex courseware is used in this course because the language has not changed significantly.