The foundational text of classical realism. Morgenthau’s argument that international politics is governed by the pursuit of national interest defined in terms of power remains the starting point for every IR theory course. He argues that statesmen who forget this — who pursue idealistic goals without regard for power — consistently fail. Even if you disagree with realism, you must understand Morgenthau before you can argue against him.

The most influential IR theory book of the twentieth century. Waltz’s structural realism — the argument that the distribution of power in the international system explains state behaviour better than human nature or domestic politics — is the baseline theory that every subsequent theorist has had to engage with. Dense but essential. Read it slowly.

The foundational text of neoliberal institutionalism. Keohane asks: if realists are right that states are self-interested, why do international institutions exist and why do states follow their rules? His answer — that institutions reduce transaction costs and enable mutually beneficial cooperation even without a hegemon — is the liberal response to realist scepticism about international organisations.

The foundational text of constructivism. Wendt’s argument that “anarchy is what states make of it” — that the competitive, self-help character of the international system is a social construction rather than an objective structural fact — transformed IR theory. States’ identities and interests are not fixed but shaped by interaction, norms, and shared understandings. Dense but worth the effort.

The definitive statement of offensive realism. Mearsheimer argues that great powers are structurally compelled to maximise their relative power because they can never be certain of other states’ intentions in an anarchic world. His prediction that China cannot rise peacefully — that US-China conflict is structurally inevitable — is the most debated proposition in contemporary IR. Clearly written and genuinely gripping.

The most controversial IR book of the post-Cold War era. Huntington argued that future conflicts would be driven by cultural and civilisational differences rather than ideological or economic competition — that the fault lines of the 21st century would run between Western, Islamic, Sinic, Hindu, and other civilisations. Widely criticised for oversimplifying and for its Islamophobia accusations, but also widely cited as prescient after 9/11 and in debates about China.

The most readable introduction to geopolitics available. Marshall explains how mountains, rivers, plains, and coastlines shape the foreign policy choices of ten major powers — Russia, China, the United States, Europe, the Middle East, Africa, India and Pakistan, Korea and Japan, Latin America, and the Arctic. Each chapter is clear, engaging, and grounded in specific geography.

A passionate and evidence-based argument that war is not an inevitable feature of human nature or international relations — that it is a historical institution, like slavery, that can be ended. Swanson marshals data, historical examples, and moral arguments to make the case for abolishing war as a political instrument. Challenging, provocative, and genuinely thought-provoking for anyone immersed in realist IR thinking.

A pocket-sized masterwork on peacebuilding. Lederach distinguishes conflict resolution — ending the immediate dispute — from conflict transformation, which changes the underlying relationships and structures that produce conflict. Short, practical, and profound. Essential reading for anyone working in post-conflict studies, development, humanitarian affairs, or peace and conflict studies.

The philosophical foundation of modern democratic legitimacy. Rousseau’s argument that political authority derives from the consent of the governed underpins everything from the UN Charter to international human rights law. His opening line — “Man is born free, and everywhere he is in chains” — frames the central question of political philosophy that IR theory inherits: what makes political authority legitimate?

The most penetrating foreign analysis of American political culture ever written. Tocqueville’s observations from his 1831 visit to America explain tendencies in American foreign policy that still operate today — the tension between isolationism and interventionism, the role of public opinion in constraining foreign policy, and the relationship between democratic culture and military power. Astonishingly relevant nearly 200 years later.

The greatest novel ever written about war and its relationship to history, power, and human agency. Tolstoy follows five aristocratic families through Napoleon’s invasion of Russia, capturing how ordinary people experience the chaos that statesmen call history. His central argument — that war is shaped by vast impersonal forces beyond any individual’s control, not by the genius of commanders — is a profound challenge to the great-man theory of international relations.

The most important political novel of the twentieth century. Orwell’s dystopia of a totalitarian surveillance state with perpetual war and the systematic destruction of truth has become the essential reference point for discussions of authoritarianism, propaganda, information warfare, and the fragility of liberal democratic norms. Big Brother, doublethink, thoughtcrime, Room 101 — these concepts have entered the political vocabulary permanently.

The definitive anti-war novel, told from the perspective of a young German soldier in World War I. Where strategic studies analyses the causes and conduct of war, Remarque shows what it does to the humans who fight it — the disillusionment, the psychological destruction, the gap between the patriotic rhetoric at home and the reality in the trenches. Banned by the Nazis in 1933 for obvious reasons. Still devastating nearly a century later.

The most practical book on this list. Updated regularly by Georgetown’s School of Foreign Service, it maps every major career path in international affairs — government, diplomacy, international organisations, NGOs, think tanks, journalism, international business — with honest assessments of what each involves, what qualifications help, and how to break in. Essential reading before any IR student applies for anything.