Courier riding is probably the most interesting, especially if attached to a regimental or battalion headquarters. Military communication systems have been considerably altered by the use of field radio but not as much as one would imagine. Many movements or actions cannot be put into effect without written orders. Maps and the transparent overlays (they are celluloid sheets which fit over a designated map and have a road or position marked on it which shows its place on the map underneath) naturally, cannot be sent by radio or telephone. Also in the modern warfare of movement the signal corps, although fast and efficient can not keep the pace of fast advancing columns with field telephone lines and in a retreat, orderly or not, telephone and radio communications are the first branches of the service which are hors de combat. So Napoleon’s courier who, when asked if he were wounded, answered, “Nay, Sire, I am dying,” from the back of his horse but would now answer from astride a motorcycle.