ABSTRACT
During the Twentieth Century, the discipline of International Relations was largely dominated by the realist paradigm. This school was behind the publication of a number of very important texts in both Europe and the United States. Two major elements explain the importance of the realist paradigm: first, the history of twentieth century international relations (two World Wars and innumerable local wars) weighed considerably on the development of political philosophy; second, the realist approach resonated with post-1945 systemic theory, particularly in the United States, and responded to a need to explain the bipolar world and the new global role of American power. Nonetheless, the second half of the twentieth century witnessed the emergence of several post-realist theories whose roots can be traced through the history of ancient and modern political thought. Their development was fuelled by the need to explain new phenomena such as complex global economic interdependence, the proliferation of organizations that promote peaceful cooperation among nations, the emergence of transnational society and public opinion, and the success of the European Union as the most advanced regional grouping of neighboring states.
