Quotes About Codebooks

Secret intelligence from Berlin was of small value to the conquering Soviets. It was no longer worth the risk. The spies had burned their codebooks and hidden their radio transmitters in the rubble of bombed buildings. They had agreed never to speak of their work. They had been brave, they had shortened the war, and they had saved lives, but it was too much to expect the defeated German people to see things that way. Their courage would remain forever secret.

Only holders of a cipher "key" could divine the underlying text, but possessing the codebooks made the whole process of solving the messages far simpler. To exploit these treasures the Admiralty established Room 40.