Counterinsurgency is defined as efforts to defeat and confine a rebellion against a constituted authority. While it has become a buzz-word in the last twenty years, it is as old as society itself. This concise history discusses the development of modern counterinsurgency over the last two hundred years, beginning with the origins of modern insurgency from the concept of ‘small wars’ and colonial warfare, through the ideas of early insurgents including Clausewitz and the theories of Lawrence of Arabia, to the methods of 20th-century insurgents, including Mao and Che Guevara.It then examines a number of post-1945 insurgencies and how western armies have tried to counter them, in particular how the French tried to counter insurgencies in Indochina and Algeria, and then the US in Vietnam, and the reaction to the American experience there. This is compared with the British approach in the years after World War II, particularly in Malaya, but also in Kenya and Northern Ireland. Against that backdrop there is an examination of counterinsurgency in Afghanistan and Iraq, the rise of COIN literature, and the subsequent backlash against that literature. The book concludes with a discussion on the future of COIN.