The years 1915–17 of World War I saw the Imperial German Army forced to adapt to the new realities of static trench warfare. Prewar uniforms and equipment had to be modified, for both utility and economy; on battlefields ruled by machine guns and artillery the steel helmet reappeared, as well as masks to protect against poison gas. The fashionable cavalry regiments soon proved irrelevant on the Western Front; many were dismounted to join the infantry, while new types of unit usurped their prestige – assault battalions, and the air corps. This second volume in a three-part sequence offers a mass of detail on organisation, uniforms and insignia, illustrated with rare photographs and meticulous colour artwork.