Reddit reviews International Systems in World History: Remaking the Study of International Relations

I think the discussion here has been pretty thorough, but if this is a question which has been buggin' you, I highly recommend Buzan's International Systems in World History where he traces the development of international systems (defined as broadly as possible) back into prehistory.

This is relevant to your question because if we say that the global order in which we now live is a condition of our time, rather than an enduring feature of the international system, it makes sense to go back and look at how various international systems evolved.