Although the British army developed a separate and highly skilled Pioneer Corps in World War II, this was not the case in World War I. Construction duties were carried out by "pioneer" battalions of regular infantry regiments. Periodic German breakthroughs drove the pioneer battalions into an active combat role, and they fought in most of the major battles of the Western Front. Mitchinson's work is the first detailed study of the active duty and social background of the men in these unique units.