The Principle Of Non-intervention In The Domestic Affairs Of States Is One Of The Most Venerable Principles Of International Law. Although Not Expressly Mentioned In The Charter Of The United Nations, At Least As An Inter-state Prohibition, The Principle Currently Appears In A Plethora Of Treaties And Un General Assembly Resolutions And Has Been Invoked Like A Mantra By States Of All Geographical And Political Denominations. Despite This, The Determination Of Its Exact Content Has Remained An Enigma. This Book Solves This Enigma By Exploring What Constitutes An 'intervention' In International Law And When Interventions Are Unlawful. These Questions Are Approached From Three Different Perspectives, Which Are Reflected In The Book's Structure: Historical, Theoretical, And Systematic. Marco Roscini. At Foot Of Title: Fritz Thyssen Stiftung Für Wissenschaftsförderung And Geneva Academy. Includes Bibliographical References And Index.