Offers the official TYPO3 documentation, tutorials, the extension repository with downloads, organisation of the developer teams and a community with mailing list and a blog.

Website of the non-profit organisation organising the development of the content management system. Background information, how to become a member, and activity reports.

Great parts of the main TYPO3 documentation can be found in this Wiki ranging from helpful knowledge for beginners to advanced knowledge for extension programmers.

Official API of the TYPO3 source code listing files, classes and packages.

High-end open source content management system with a host of features. Written in PHP/MySQL. Large and active community, documentation and support resources.