The document provides an overview of key concepts in international relations including geopolitics, geo-economics, realism, idealism, Marxism, feminism, postmodernism, and constructivism. It then discusses the emergence of the modern nation-state in Europe following the Thirty Years' War and Treaty of Westphalia, which established principles of state sovereignty and non-intervention. Political and economic revolutions in Europe led to the development of democracy, nationalism, and industrialization.