Giovanni Arrighi is known for his long historical approach to understanding the current world of International Political Economy. One of his best known works is "The Long Twentieth Century." Very easy and inexpensive to get, and talks about the development of successive hegemonic capitalistic powers starting with the Spanish and continuing up to the United States in the present day. It is pretty heavy in the IPE, but if that doesn't bother you then it is an interesting and thought provoking book.