"During part of 1941 and 1942, when the Luftwaffe was busy in Russia, the German radio regaled its home audience with stories of devastating air raids on London. Now, we are aware that those raids did not happen. But what use would our knowledge be if the Germans conquered Britain? For the purpose of a future historian, did those raids happen, or didn't they? The answer is: If Hitler survives, they happened, and if he falls they didn't happen."