This book is an attempt at a comprehensive presentation of the history of humanitarian intervention in the long nineteenth century, the heyday of this controversial doctrine. It starts with a brief presentation of the present situation and debate. The theoretical first part of the book starts with the genealogy of the idea, namely the quest for the progenitors of the idea in the sixteenth and seventeenth century which is a matter of controversy. Next the nineteenth century ‘civilization-barbarity’ dichotomy is covered and its bearing on humanitarian intervention, with its concomitant Eurocentric/Orientalist gaze towards the Ottomans and other states, concluding with the reaction of the Ottomans (as well as the Chinese and Japanese). Then the pivotal international law dimension is scrutinized, with the arguments of advocates and opponents of humanitarian intervention from the 1830s until the 1930s. The theoretical part of the book concludes with nineteenth century international political theory and intervention (Kant, Hegel, Cobden, Mazzini and especially J.S. Mill). In the practical second part of the book four cases studies of humanitarian intervention are examined in considerable detail: the Greek case (1821-1831), the Lebanon/Syria case (1860-61), the Balkan crisis and Bulgarian case (1875-78) in two chapters, and the U.S. intervention in Cuba (1895-98). Each cases study concludes with its bearing on the evolution of international norms and rules of conduct in instances of humanitarian plights. The concluding chapter identifies the main characteristics of intervention on humanitarian grounds during this period and today’s criticism and counter-criticism.