Educators interested in developing interactive, web-based learning materials have an exciting, powerful tool in Adobe Flash. Flash comes with the full-fledged, object-oriented programming language ActionScript, which makes it possible to create sophisticated applets – self-contained units running within the user's browser – as well as programs that communicate with and use applications on a server. Such applets and applications are delivered to the audience through the ubiquitous, light-weight, and reliable Flash Player which runs Flash files in any browser and on any platform. The ubiquity and the consistent performance of the Flash Player as well as other features make Flash an attractive solution to needs for online delivery of interactive material.