During World War II, a flurry of coded messages were sent by the Axis powers. Data on troop movements, supplies, ship locations... all transmitted via code. But these messages didn't necessarily stay coded for long. The Allies were able to intercept, decode, and learn the vital wartime secrets contained within many of these transmissions. These codebreaking efforts were vital in ending the war. And the people who actually did a lot of this work were women - over ten thousand of them. Liza Mundy is the author of Code Girls: The Untold Story of the American Women Code Breakers of World War II, and she tells us about this little-known part of American history.