Sharepoint AAM explained

http://blogs.msdn.com/b/sharepoint_strategery/archive/2013/10/01/aams-explained-redux-and-presentation.aspx

http://blogs.msdn.com/b/sharepoint_strategery/archive/2013/05/27/alternate-access-mappings-explained.aspx

http://technet.microsoft.com/en-us/library/cc261814(v=office.12).aspx