This book focuses on just war and on humanitarian intervention, both of them controversial themes yesterday as well as today. The study covers the following: 1. International ethics and norms: irrelevant or indispensable? Revisiting a persisting debate.2. The just war doctrine from Antiquity until today, with emphasis on Aristotle, Cicero, Augustine, Aquinas, Vitoria, Gentili, Suarez and Grotius, concluding with Michael Walzer.3. Intervention and the non-intervention norm: an overview from the 18th century until today.4. The roots of humanitarian intervention: just war against tyranny, with emphasis on Vitoria, Gentili, Suarez, Grotius, the monarchomachs, Bodin and Vattel. 5. Humanitarian intervention in international law: a hundred years debate (1830-1939).6. Intervention and non-intervention in international political theory during the long 19th century: Kant, Hegel, Cobden, Mazzini and J.S. Mill.7. Humanitarian interventions in the course of the 19th century: the Greek case (1821-1831), the Lebanon-Syria case (1860-1861) and the Bulgarian case (1876-1878).8. Humanitarian intervention cases during the Cold War.9. Humanitarian intervention cases in the post-Cold War era (1990-today). 10. The contemporary humanitarian intervention debate: the dilemmas involved; the search for the appropriate reaction at UN level; and the key issues, according to its advocates, on how to proceed with humanitarian intervention if the need arises.