For some reason the standard field "Manager" (type hierarchy) on the User object seems to be limited to displaying on the User page only.  It is not visible via the API (using APEX Explorer) nor can it be selected in a standard SF report.  I see nothing in the API reference guide that suggests this particular User object field can not referenced or queried via the API. 

 

Am I missing something?  Is this not possible?  Any insight would be appreciated.  Thanks...