In World War II the Corps of Engineers superintended the largest construction program in the nation's history, providing the home base for a United States Army that grew to more than eight million men and women. The Corps-related construction work included development of the facilities for making atomic bombs. In telling the story of these herculean efforts the authors set unprecedented standards: no detailed and scholarly history on the subject of construction has ever before been undertaken in this country. Other aspects of the domestic contributions of the Army Engineers in the war have been covered in the first volume of this subseries to be published, Troops and Equipment, and a second told the story of the Engineer effort overseas in the war against Japan. A final volume still in preparation will relate the activities of Engineers in the Mediterranean area and Europe in the war against Italy and Germany. While this volume presents the story of military construction during the war primarily from the point of view of the Corps of Engineers as revealed in its records and by its participants, it does justice also to the work of the Quartermaster Corps from which the Engineers inherited responsibility for military construction in the United States in 1940 and 1941.