No weapon of the twentieth century has done more to extend the war zone to civilian populations than the bombing aircraft. This development was foreseen well before the first bomber made its appearance; prophetic writers predicted its invention and foretold its use against the urban masses. Not until aviation technology had advanced somewhat did politicians and airmen take up seriously the idea of strategic bombing, as they came to see that the air arm possessed potentialities beyond purely tactical and subordinate roles. By 1916, during the First World War, responsible political and military authorities were to be found on both sides prepared to argue that the war could be won by striking through the air at the enemy’s industrial might or at the national will by attacks upon the civilian population.