12.13 Onward! Classes and inheritance open up a world of potential for sharing common information among many objects. Object-oriented programming is the basis of all code in ActionScript. Whether or not you use every aspect of classes and objects in your scripts, understanding the general concepts involved is an essential part of understanding the Flash programming environment. Confidence with object-oriented programming greatly influences confidence with ActionScript in general. For further reading on object-oriented programming with ECMA-262-derived languages, see Netscape's documentation for JavaScript, Details of the Object Model: - http://developer.netscape.com/docs/manuals/js/core/jsguide/obj2.htm
David Flanagan's canonical text, JavaScript: The Definitive Guide (O'Reilly), also provides valuable information on OOP in JavaScript. For a general introduction to OOP from a Java perspective, see Sun's Object Oriented Programming Concepts (from "The Java Tutorial"): - http://java.sun.com/docs/books/tutorial/java/concepts
For a complete online walkthrough of OOP in ActionScript, try Robin Debreuil's tutorial: - http://www.debreuil.com/docs/
And, for the curious, here's an extensive set of articles attempting to deflate the oft-hyped OOP system. Whether you agree or disagree with the author, you'll likely learn from the discussion. - http://www.geocities.com/tablizer/oopbad.htm
We've certainly come a long way, and I hope you're still as enthusiastic about the journey as I am. Next we'll explore the most important class of objects available in ActionScript, the MovieClip class. | 
