In 1914 the BEF did not have any technical units to deal with the problems of water supply, electricity, machinery or workshops forward of the L of C. With the steadily increasing number of troops, and the consequent extensions of fronts, with the demands of all sorts of trench warfare contrivances, and requirements of a higher degree of comfort in living conditions the lack of skilled personnel became apparent to all. However, the problem of water supply in the Somme battles brought matters to a head and resulted in the formation during the winter of 1916-17 of an Electrical and Mechanical Company for each Army, followed in the summer of 1917 by a similar number of Army Workshop Companies RE. This volume traces in details the story of these units and the nature of their work. Numerous tables and lists provide details of the personnel and their trades in an E & M Company, types of equipment in use, drawings of equipment and a diagram showing a typical organization for work in an E & M Company. One plate shows the principal electric stations in British Army areas and another illustrates the electric lighting of the Hulluch-Cuinchy subways. This is a comprehensive account.