Gordon L. Rottman 
Vietnam Gun Trucks [PDF ebook] 

While Vietnam is usually perceived as an infantry war, with US forces deploying by helicopter, the long supply lines that led to their inland bases had to be traveled by ground vehicles. The 8th and 48th Transportation Groups were responsible for hauling supplies through the long, dangerous roads of Vietnam, and they often found themselves the target of ambushes, attacks, and sniping. In response to this, vehicle crews began to arm trucks with machine guns and armour them with sandbags. While these proved less than ideal, the concept was considered valid, and more and more gun trucks appeared, sporting heavier weapons and armor. Written by a Vietnam veteran, this book traces the development of these gun trucks from the jury-rigged originals to the powerful armoured vehicles that appeared later in the war.