I do not envy you, DeBord, Negri and all these other Po-Mo marxists are not easy to grasp, you need a lot of knowledge back in your head, from Spinoza, Nietzsche, Marx and Freud to Althusser, Deleuze, Guattari and Derrida, etc.
Personally I don't grasp neither the situationists nor the post-autonomists very well, but I would like to recomend the book "Empire's new clothes". It might really help you understand Empire.
http://www.amazon.com/exec/obidos/tg/detai...163300?v=glance


