Hundreds, perhaps thousands, of American and South Vietnamese soldiers sweep across the Mekong Delta in a search-and-destroy operation—but the enemy has disappeared. A terrorist's bomb devastates a servicemen's billet in Saigon, and in the ensuing confusion the bomber escapes. An enemy who fights with captured weapons; soldiers in sandals; an ambush along a jungle trail—what kind of war is this? Who and where are the enemy? How can they be fought?

Sir Robert Thompson spent twelve years in Malaya during the period of insurgency known as the Emergency. From 1961 to 1965, he headed the British Advisory Mission in Vietnam. Now, after long study of the theory of guerrilla warfare as well as firsthand observation of counterinsurgency he has written a practical manual on what the Communist world terms a "people's revolutionary war."

On the basis of his experience in Malaya and Vietnam, Sir Robert demonstrates how poorly armed Communist guerrilla forces can harass and terrify a large-scale conventional army. But he also shows how these guerrillas can be stopped, short of general war and without an enormous cost in men, money, and materiel. Tracing the step-by-step progression from the subversive build-up phase through the guerrilla phase of terrorist activity and finally the insurgency stage of open warfare, he describes the measures that have proved most effective in slowing down the progression, in isolating the guerrillas, and in defeating the insurgency. He assesses the effectiveness of the strategic-hamlet plan and the contribution of a large outside power such as the United States. Because he believes that military operations will not succeed in destroying the guerrilla machinery until the underlying political subversive organization has been destroyed, Sir Robert emphasizes the administrative tactics of establishing a politically and economically stable nation out of a multitude of rural agricultural communities. His book is a vivid and detailed blueprint of how Communist insurgency can be met—and bested.