Each of these three perspectives adopts different assumptions to sim- plify reality and render it more explicable. Liberals assume that individuals are the proper unit of analysis, while Marxists and Realists make similar assumptions for classes and nation-states, respectively. The three perspec tives also differ on the inevitability of conflict within the political economy. Liberals believe economics and politics are largely autonomous spheres, Marxists maintain that economics determines politics, and Realists argue that politics determines economics These three perspectives lead to widely different explanations of spe- cific events and general processes within the intemational political my. Their differences have generated numeFous debates in the field, many of which are contained in the readings herein. Overlying these perspectives are two additional debates on the relative importance of international and domestic factors, and of social or state forces, in determining economic policy.