This volume deals principally with the story of the British Signal Service in France. It was only two years prior to the outbreak of war, in 1912, that the Signal Service was formed as separate and integral branch of the Royal Engineers. In 1920 it became a Corps in its own right - the Royal Corps of Signals, taking precedence immediately after the Royal Engineers. Throughout the chapters of this narrative three main themes can be detected: the evolution of signal policy, of signal organization, and of signal practice. Several definite phases of the war as it affected the Signal Service can be identified, and of these the most important are: the early mobile phase; the stationary (trench warfare) phase of 1915-1917; the retreats of the spring and early summer of 1918; and the final advance to victory. Each phase reacted on signal policy, organization, and practice alike though the first was less affected than the other two. This is a very well written account in which the author has woven together the three main themes into a continuous narrative, adhering as far as possible to a chronological order of facts. At the end are a series of personnel and transport establishment tables of various Signal units, and tables listing signal trades and the number of personnel in each trade present in various units. In all these tables figures are given for each year of the war demonstrating clearly the growth of the Service not only in manpower but also in the skills and trades required. Finally, tnere are a number of plates depicting signals/wiring diagrams.