In 2000, the International Panel of Eminent Personalities that investigated the genocide in Rwanda concluded that intervention could have saved thousands of lives that perished in less than hundred days. The finding made it clear that Africa as a continent needed to develop in earnest the normative and institutional framework to save the lives of its inhabitants faced with massive crimes. In 2001, African states established the African Union endowed with a right of intervention in side its member states against genocide, crimes against humanity and war crimes. This book investigates the legality of the African Union’s right of intervention against genocide, crimes against humanity and war crimes under international law, critically analyses the constituent elements of the African Union’s right of intervention and elucidates the norms and institutions relevant for its effective implementation. The book uses the Darfur atrocities and the surrounding events to explain the challenges in the application of the African Union’s right of intervention against genocide, crimes against humanity and war crimes.