Subversion (SVN) is a very popular open source versioning system. It manages files, directories, and changes made to files and directories over time by single of multiple users. If you have the time to thoroughly learn SVN, the only book you should read is available online for free. It can be found at http://svnbook.red-bean.com. However, if all you want to do is get started with SVN within an hour, you have come to the right place.