The theory began with Ludwig Gumplowicz with further development by Franz Oppenhiemer. You will certainly want to read Albert J. Nock and his book, "Our Enemy, the State".
There's a free full-view of Nock's book on google books.. http://books.google.com/books?id=Fl...&resnum=1&ved=0CDcQuwUwAA#v=onepage&q&f=false you can download the PDF of the book HERE
Shikamaru, Are you saying that all states in the past were exploiting of the poor? Or that even small African nations were not build on mutual benefit? It is easy to see all modern states like this. but I don't believe it has always been like that.
All states in the past and presently are built on exploitation. No state is designed for mutual benefit. It is designed for the benefit of its founders, directors, or the elite. If you can find me an example of a state not founded on exploitation, I'll consider it. What you are indirectly referring to is what has been defined by Hobbes, Locke, and Rousseau as the "social contract theory" of the state.
This pretty much ties in with "conflict theory". It finds its way back to American shores in the ideas of C. Wright Mills. It's an honest look at how things can be easily described in their current state, but the conflict theorists did actually offer some pretty good solutions.