Philip Bartlett's diaries, here edited by his son and published for the first time, provide an account of action in the Royal Naval Air Service and are a record of a pilot's life in the early days of aerial warfare and of the first strategic use of the bomber in war. From daytime and night-time flying with only the Belgian coast as an aid to navigation, the account moves to the bombing of the U-boat bases to the counter-attacks against the German Gotha raids on London, and the RNAS's support for Haig's drive to the coast, which ended in the mud of Passchendaele. On 18th March 1918 the author's squadron found itself opposite St Quentin, directly in the path of Ludendorff's massive thrust, which drove the broken British Vth Army back over the old Somme battlefield and nearly into the sea. Attacked by the elite of Germany's aces, 5 Squadron RNAS flew continuous desperate sorties against troop concentrations and railheads from airfields which were overrun time and again. This was last big operation for the RNAS before it merged with the new RAF. This day-to-day account portrays the curious mixture of grim reality and abstract wonderment engendered by fighting in the new and exciting arena of the sky, and an interlude is provided by operational flights made on the experimental Sopwith BI bomber which was the ancestor of the torpedo bomber.