ABSTRACT
It helped to win the battle of the Atlantic and turn the tide of war at Midway, led to the midair shootdown of Admiral Isoroku Yamamoto, disclosed defensive details of Hitler’s Atlantic Wall, made possible dozens of tactical victories during the Allied invasion of Europe, enabled American pigboats to strangle Japan by sinking her convoys.1 Near the war’s end, American solutions of French and Latin American codes helped the United States shape the United Nations the way it wanted.2
