Quite simply, without engineers the U.S. Army would have been unable to fight World War II. The men of the Corps of Engineers, with the strength of more than 700 battalions mobilised during World War II, were tasked with every imaginable engineering challenge. In rear areas and back in the United States they built the facilities essential for everyday military life: showers, toilets, barrack blocks, military hospitals, training camps, storage depots, and much more. To keep logistics flowing to the front, they constructed or repaired thousands of miles of roads and bridges, plus built airfields to support Allied strategic and tactical air operations. Engineers also created endless chains of defensive positions, from simple trench systems to complex bunker networks, as well as retrieving damaged vehicles and equipment from still-contested battlefields.  Combat engineers, meanwhile, occupied some of the most dangerous frontline roles in the American armed forces. Heavily armed with demolitions and weapons, plus weighed down by engineering tools and even driving armoured bulldozers, they were tasked with destroying enemy strongpoints, bridges, equipment, vehicles and many other obstacles to the advance, in both overland and amphibious operations. Building the Battlefield: Tactics and Techniques of U.S. Army Engineers in World War II brings together an exceptional collection of primary sources from engineering field manuals, technical manuals, and other official publications. They provide a detailed insight into the work and skills of the U.S. Army engineers, including building a field fortification, laying and defusing mines, making a contested river crossing, or camouflaging a defensive position properly. Through these texts, we gain practical insight into the exceptional individuals who often combined first-rate infantry fighting skills with engineering skill and problem-solving ingenuity.