This is a remarkably detailed review of the Royal Engineers (RE) and its varied units in peacetime and the tremendous expansion that took place during the course of the war including the formation of many new units that did not exist before the war. What is interesting is how wide were the responsibilities of the Corps, which are fully described, chapter by chapter, thus we read and learn about: bridging units, electrical and mechanical companies, tunnelling companies, forestry units, the inundation section, tramway and foreway companies (the latter being a new service, formed in March 1918, to distribute supplies forward of railhead).Then there were transportation units, the postal service, the signals service, which separated from its parent Corps in 1920 and became the Royal Corps of Signals, meteorological sections, camouflage, field survey, mapping, anti-aircraft searchlight, gas (the Special Brigade) and yet more besides. It makes for fascinating and, I am sure, very enlightening reading for many. At the end there are tables showing all these and their growth during the war and the numbers serving in the various theatres of war. The RE regulars and special reserve began the war with 1,056 officers and 10,304 men; by 1 August 1917 these figures had become 8,886 and 230,500. In this same period the TF grew from 13,640 all ranks to 56,282.