TYPO3 is the enterprise-level content management system for the Web. It is large, feature-rich and very flexible a lot of this flexibility comes through extensions written by the community. Extensions make it possible to use TYPO3 to drive any type of website, including e-commerce, blogs, social networks, catalogs, and many more. TYPO3 can be completely customized using extensions; however creating an extension can be a challenging task. This tutorial deals extensively on creating files and extensions using Typo3. Although the book covers all generation options and emphasizes important decisions that extension developers should be aware of.