On 30 March 1972 the South Vietnamese positions along the Demilitarized Zone (DMZ) that separated the North from South Vietnam were suddenly shelled by hundreds of heavy guns and multiple rocket launchers. Caught in a series of outposts of what was the former `McNamara Line', the shocked defenders had just enough time to emerge from their bunkers at the end of the barrage before they were attacked by regular North Vietnamese Army divisions, supported by hundreds of armoured vehicles that crashed though their defensive lines along the border. Thus began one of the fiercest campaigns of the Vietnam War but also one of the less well documented because by then most of the American ground forces had been withdrawn. Following on from the details of the downsizing of American forces and the setting up of the`Vietnamization' policy, the build up of both the Army of the Republic of Vietnam (ARVN) in the South and the People's Army of Vietnam (PAVN) in the North is discussed at length. A special emphasis is devoted to the study of the development the North Vietnamese armoured corps that would spearhead the coming offensive. Consequently, the nature of the war changed dramatically, evolving from a guerrilla one into a conventional conflict. The South Vietnamese resistance shuddered, and then crumbled under the communist onslaught, putting Hue the ancient imperial capital at risk. It was only thanks to US airpower, directed by a small group of courageous American advisers, which helped to turn the tide. Under the command of a new capable commander, the South Vietnamese then methodically counterattacked to retake some of the lost ground. This culminated in the ferocious street fighting for Quang Tri. This first volume describes the combat taking place in the northern part of South Vietnam, and uses not only American archives but also Vietnamese sources, from both sides. The book contains 130 photos, five maps and 18 colour profiles. Asia@War - following on from our highly-successful Africa@War series, Asia@War replicates the same format - concise, incisive text, rare images and high quality colour artwork providing fresh accounts of both well-known and more esoteric aspects of conflict in this part of the world since 1945.