The Secret Code Breakers of World War II ======================================== Over 10,000 women cracked enemy codes in WWII and then vanished from the record. Liza Mundy's Code Girls brings their story back, and we're unpacking it in this episode. ---------------------------------------- SAM: Hey there, welcome back to 7 Minute Books. I'm Sam, and today we're talking about Liza Mundy's Code Girls, the hidden history of the women code breakers of World War Two. Sophie, did you know that more than ten thousand women did this secret work and almost nobody knew for decades? SOPHIE: Hey there Sam, I'm so glad you picked this one. Liza Mundy's Code Girls is a masterful work of historical recovery, about the women who broke enemy codes and how a whole generation of brilliant women was written out of history. SAM: The book opens in 1942, with the military drowning in intercepted enemy messages and desperately short of code breakers. So they went looking for the smartest young women they could find. SOPHIE: Recruiters went to elite colleges like Wellesley, Mount Holyoke, Barnard, and and Vassar. They wanted women who were great at math, or languages, or just loved puzzles. SAM: The pitch was vague. It was basically 'come do secret war work.' Don't ask questions, and tell no one, not even your parents. SOPHIE: That secrecy was total. Some of these women kept it for over fifty years, even from their own families. SAM: Can you imagine that kind of silence? It sounds like a strange, lonely heroism. SOPHIE: They worked in windowless buildings in D.C., like Arlington Hall and the Navy's Building 4. They used IBM punch card machines and the bombe to break the German Enigma code. SAM: But the most important tool was their own intuition. That intuition cracked the Japanese diplomatic code called Purple before Pearl Harbor. SOPHIE: A woman named Genevieve Grotjan made the crucial break in 1940. She realized she had found the key to the Japanese cipher machine. SAM: There were so many heroines. Elizebeth Smith Friedman had been breaking codes since World War One, and Agnes Meyer Driscoll, 'Miss Aggie,' fought Japanese naval codes for years. SOPHIE: Mundy's big argument is that these women weren't support staff. They were the intellectual engines of the cryptanalytic effort. SAM: And the core of the book is the thousands of women working on the JN-25 naval code, which the Japanese thought was unbreakable. SOPHIE: They worked in teams. Some built massive card catalogs of code groups. Others studied radio traffic to track enemy ships, and the real cryptanalysts stared at numbers for hours. SAM: They learned to recognize the fingerprints of Japanese code clerks, tiny personal habits in the signals. SOPHIE: That pattern recognition helped win the Battle of Midway. The women figured out Yamamoto was planning an attack on Midway, and Nimitz set a trap. SAM: And that victory is often credited to male commanders, but it was made possible by hundreds of women working through sleepless nights. SOPHIE: Mundy doesn't hide the cost. The women were paid less than men, denied promotions, and treated with condescension. SAM: There's a heartbreaking story about a woman who worked on the code that shot down Yamamoto's plane. She spent her life wondering if she had helped kill a man, and she could never talk about it. SOPHIE: That kind of quiet trauma is so easy to miss. SAM: After the war, they were sent home and told to forget everything. The military locked their work away, and official histories gave credit to a few men. SOPHIE: So their contributions were actively erased. Many never told their children, and they died without recognition. SAM: Now here's the twist. The punch card machines and the logic they used were direct ancestors of modern computers. They were, in a sense, the first computer programmers. SOPHIE: Yes. They were literally called 'human computers' before the machines existed, and their skills became the foundation of software. SAM: So the phone in my pocket owes something to a woman in a windowless room in 1943. SOPHIE: Mundy also shows that they were motivated by patriotism and a love of puzzles, not by a desire for fame. SAM: And that's what makes the book so intimate. It's about individual women with sharp minds and quiet determination. SOPHIE: Yeah, and the way Mundy weaves their personal stories into the bigger picture is just powerful. SAM: You know, I was skeptical at first. I thought, 'surely she's exaggerating.' But the interviews and declassified documents back it all up. SOPHIE: And even the way she describes their nervous exhaustion, it's so vivid. They couldn't sleep, they couldn't share the load. SAM: Right. They carried the stress entirely alone. SOPHIE: And yet they kept going. That's what makes them heroes to me. SAM: So here's the one thing I'm taking away. It's that heroism isn't always the soldier on the front line. Sometimes it's the woman in a dark room, trying to find the one number that saves a ship. SOPHIE: And honestly, if you want to go deeper, the whole library's over on 7minutebooks.com/app, with more than 6,000 fiction and nonfiction titles you can read or listen to in any language. It starts at 2.99 a month, 9.99 a year, or 19.99 for lifetime access, and many titles include infographics too. SOPHIE: Code Girls reminds us that the sharpest weapons are often patient minds, and that history is full of women who deserve a second look. We'll see you in the next one.