I am curious if there is any survey style book that focuses on how societies organized their administrations. Although, if you know specific books about specific groups, that is fine too.
Ruling the Later Roman Empire by Christopher Kelly is pretty accesible. Although it has the rather narrow focus on the later Roman Empire.
Empire of Honour by J.E. Lendon is quite good and has a broader scope. But I think it may be out of print.
I'm sorry for the Roman focus. It's just what I know more. Empire of Honour does sort of touch on other empires (as Rome took some existing administration into their own).