Col. Frank Rowlett, whose genius helped on the eve of the Second World War to break Purple, Japan’s highest diplomatic cipher, some years ago told an audience at the National Security Agency of the most thrilling moment in his luminous career as a cryptanalyst: “About two o’clock one morning in early July 1945, Lt. Hank Graff, one of the linguists assigned to the translation of the deciphered Purple messages, called Gen. [W. Preston] Corderman, the head of the Army Security Agency, and myself at our homes and asked that we come to the operations area in B building at Arlington Hall Station, where the Purple intercepts were processed. When we arrived, we found that he had just translated a message from Tokyo to Moscow that directed the Japanese ambassador in Moscow to contact the Kremlin to try and intercede with the Allies on behalf of Japan for an honorable peace.”

So it was that at age twenty-three, on duty alone in an eerily quiet room, I became both the first person on the Allied side to know that the last of the Axis powers stood on the verge of surrender and the instrument through which President Truman and Prime Minister Churchill learned the glorious news a few minutes later.