This work defines the laws of counterinsurgency warfare. It is a new edition of a classic work, which outlines lessons from the 1950s and 60s that are relevant to today's conflicts. It is part of the "PSI Classics in the Counterinsurgency Era" series. This book provides an analysis of how to countermine insurgency, and of the elements that might hinder its defeat. Inspired by his military experiences as a French military officer and attache in China, Greece, Southeast Asia, and Algeria, the author realized the "need for a compass" in the suppression of insurgency, and he set out to "define the laws of counterinsurgency warfare, to deduce from them its principles, and to outline the corresponding strategy and tactics." Written in 1964, the book in its new printing is as relevant now as it was forty years ago. "Counterinsurgency Warfare" provides the template for the defeat of today's insurgents and terrorists. - Revolutionary war: nature and characteristics -- The prerequisites for a successful insurgency -- The insurgency doctrine -- Counterinsurgency in the cold revolutionary war -- Counterinsurgency in the hot revolutionary war -- From strategy to tactics -- The operations -- Concluding remarks