This chapter offers an historical grounding in interwar international relations. It tracks and analyses the progress of international relations in the period between World War I (1914–18) and World War II (1939–45), both of which are rightly seen as two major and formative conflicts in international history and indeed for the study of International Relations. It is sometimes assumed that the two World Wars were primarily European affairs, at least in their origins, and reflected the persistence of European predominance in a fast-changing world. Yet these were truly global and globalising wars, as reflected in their causes, courses and consequences, the technologies they employed and the ideas they helped generate. The period in between the wars was a turbulent and unstable one. It foreshadowed European decline and witnessed the rise of the United States, the challenge of the Soviet Union and the Far East and, more gradually, of peoples around the world subject to imperial rule – in short, the interwar period provided the foundations for the international system that developed over the following decades. Many of its contours are still visible today.

The final chapter takes the researched practitioner to some next steps along their leadership journey. Numerous topics concerning social justice leadership are introduced and explored at an entry level. The intersectionality of various theories and concepts are presented with the goal of personal and professional growth for each individual leader.

Public international law is a worldwide legal system which regulates the conduct of states (countries) and other actors, both in their international relations and within states’ territories. It governs many areas, such as sovereignty over territory; rights and responsibilities at sea; environmental protection; human rights and the suppression of international crimes; trade and investment; the use of military force; responsibility for breaches of the law; and the settlement of disputes. This chapter introduces the main features of public international law, including its history, sources and purposes. It outlines what the law regulates, who has rights and bears obligations under it, and how it is implemented and enforced. The chapter then considers jurisprudential debates about the nature of public international law as ‘law’ and the reasons for compliance with it, and concludes with discussion of some key critical theories.

− Over the last decade, ESG-Agency scholars have increased their use of social and system dynamic theories, participatory and actorness approaches in agency theories, and justice approaches within critical theories.− Qualitative and multiple qualitative methods are the most widely used approaches in research on agency in earth system governance, with very slowly growing methodological pluralism. − In the future, scholars in this field may benefit from the integration of cross-disciplinary and increasingly complex methods in an effort to foster linking of environmental sciences more broadly into environmental governance research.

− ESG–Agency scholars frequently use power as an explanatory variable, but often without definition or theoretical conceptualization. − Reflections on power in earth system governance research are divided between agency-centered (power to) and structure-centered (power over) perspectives, which mirrors the historic schism between liberal and critical International Relations scholars. − In the future, more comprehensive conceptualizations of power will strengthen the persuasiveness of normative arguments in ESG–Agency scholarship.