This textbook provides a comprehensive introduction for individuals who are new to the discipline of International Relations or World Politics. It features three distinctive elements. First, it posits that understanding the international political economy is essential before delving into analyses of war and security, emphasizing that economic interdependence, arising from international cooperation, is a central theme in international relations. Second, the textbook recognizes that strategic interaction — where the decisions of one entity and future outcomes depend on the choices of another — is a core component of international relations. It also utilizes four key concepts in its exploration of the field: Us and Others, Disparity and Dissatisfaction, Trust and Distrust, and Legitimacy and Illegitimacy. Lastly, the textbook is attuned to the methodologies of the Social Sciences, including descriptive, causal, and deductive inferences, and it stands out for its commitment to fostering methodological awareness.

Atsushi Tago is a professor of International Relations at the School of Political Science and Economics at Waseda University. Tago earned his Ph.D. in Advanced Social and International Studies from the University of Tokyo in 2007. His expertise lies in the scientific analysis of international relations, with a particular focus on the American use of military force and the coalition of the willing. Additionally, he has contributed to research on nuclear proliferation, international law and politics, and mass political violence. He was the Principal Investigator for the CROP-IT (Collaborative Research on Political Information Transmission) project, which was supported by the Japan Society for the Promotion of Science. Recently, he has engaged in scientific inquiries related to public diplomacy and strategic communication, and physiological experiments on war and peace. Tago’s works appear in journals like Journal of Politics, British Journal of Political Science, Political Science Research and Methods, Political Communication, Journal of Conflict Resolution, and Journal of Peace Research. During 2017−2023, he served as a Global Fellow at the Peace Research Institute in Oslo (PRIO).  He is now the editor in chief of International Relations of the Asia-Pacific.