During the Second World War aeronautical technology gathered rapid pace. By 1945, bombers had not only greatly increased in engine power and range, but the bombs which they carried rose from 250lbs to 10 tons; the navigator's pencil and rubber of 1939 had been supplemented by infinitely more sophisticated electronic aids. Yet the success or failure of each and every bomber still depended entirely on the efficiency of every member of the crew at his individual position, the interaction and co-operation of all crew members as a body. One member of 617 squadron graphically explained that 'every time we went out, it was seven men against the Reich'. Drawing on letters, journals and diaries, John Sweetman examines the lives the bomber crews lived, from the highs and lows of their missions to the complexities of their friendships and the impact their place in the war had on the families and loved ones they left behind.