The past several pages covered a lot of ground. Let's review what we've covered so far.
An ActionScript program is a set of instructions to be executed by one of the Flash runtimes: Flash Player, Adobe AIR, or Flash Lite. ActionScript programs can be written in a text editor, Flex Builder, or the Flash authoring tool. In order to run an ActionScript program, we must first compile it into a .swf file using a SWF compiler such as the Flash compiler included with the Flash authoring tool, or mxmlc, which is included with both Flex Builder 2 and the Flex 2 SDK.
Don't worry if some of the preceding concepts or terms are new to you. We'll be applying them abundantly over the next 900-plus pages.
Now let's write some code!