Programming Firefox: Building Rich Internet Applications with XUL by Kenneth C. Feldt [Repost]

This is your guide to building Internet applications and user interfaces with the Mozilla component framework, which is best known for the Firefox web browser and Thunderbird email client. Programming Firefox demonstrates how to use the XML User Interface Language (XUL) with open source tools in the framework's Cross-Platform Component (XPCOM) library to develop a variety of projects, such as commercial web applications and Firefox extensions.