The war of 1914-18 was a remarkable and important epoch for many widely different reasons. Not least of these was that it represented the first widespread use of the aeroplane -- which many people thought would be of little military value -- as a major weapon of war. Such thinking was quickly disproved, and the aeroplanes described in this volume illustrate how the military aeroplane developed from the unarmed observation machines of 1914 to the highly effective specialized types that were in service by November 1918.