Magnolia is a free enterprise class content management system developed by obinary. Magnolia uses the upcoming standard API for java content repositories (JCR) to access its content. It has an easy to use web-browser interface, a clear API and a useful custom tag library for easy templating in JSP and Servlets.
A short summary of what you should read first.
To understand magnolia from the user side download the Usermanual first.
To see how a developer can write his templates jump to the Templater's Quickstart
More detailed informations are given here
Please use and contribute to the community documentation on the Wiki
Finally, report requests and bugs in the Issue Tracker