This book is dedicated to geopolitics in the 21st century. Several scholars from slightly different backgrounds (geopolitics, international relations, history, and political science) have come together to develop the geopolitical research program as an approach to international relations. This book includes research on the great powers that have permanent seats on the UN security council, as well as Japan and Brazil, as regional powers that may increase in influence in the 21st century international arena. Despite the methodological richness of the individual contributions, all chapters address the core(s) of geopolitical thought a the territorial and identity-based realities that shape politics, foreign policies, and grand strategies a thereby adding value to the research agenda of geopolitical studies.