Technical Documentation for System Center 2012 Configuration Manager
Download the Feb 2013 updated help files from https://www.microsoft.com/en-us/download/details.aspx?id=29901
Read all about it from The ConfigMgr Team Blog https://blogs.technet.com/b/configmgrteam/archive/2013/02/15/announcement-february-2013-downloadable-documentation-for-configuration-manager.aspx