This collection of documents, including many previously unpublished, details the role of the Army engineers in the American Revolution. Lacking trained military engineers, the Americans relied heavily on foreign officers, mostly from France, for sorely needed technical assistance. Native Americans joined the foreign engineer officers to plan and carry out offensive and defensive operations, direct the erection of fortifications, map vital terrain, and lay out encampments. During the war Congress created the Corps of Engineers with three companies of engineer troops as well as a separate geographer’s department to assist the engineers with mapping. Both General George Washington and Major General Louis Lebeque Duportail, his third and longest serving Chief Engineer, recognized the disadvantages of relying on foreign powers to fill the Army’s crucial need for engineers. America, they contended, must train its own engineers for the future. Accordingly, at the war’s end, they suggested maintaining a peacetime engineering establishment and creating a military academy. However, Congress rejected the proposals, and the Corps of Engineers and its companies of sappers and miners mustered out of service. Eleven years passed before Congress authorized a new establishment, the Corps of Artillerists and Engineers.