The African-American code-breaking unit at Arlington Hall.
The African-American code-breaking unit at Arlington Hall. Credit: Courtesy of National Security Agency

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In 1945, Jaenn Magdalene Coz wrote to her mother.

“I’m in some kind of hush, hush business. Somewhere in Wash. D.C. If I say anything I’ll get hung for sure. I guess I signed my life away. But I don’t mind it.”

Coz had been a young librarian. Then suddenly she was one of a number of librarians who had been recruited to decipher unfiled smatterings of coded messages for the U.S. Navy during World War II. She had now become a code-breaking librarian.

These five short sentences in Coz’s letter to her mother sharply captured the spirit and sentiment of thousands of women like her, code-breaking women who had done just the same in secretly signing their lives away without a pause. Their fathers and brothers, boyfriends and husbands, had gone off to fight on the front lines. But these women—more than 10,000—didn’t sit at home and wait. When their country called, they answered and they fought, too.

Looking through archives, local journalist and author Liza Mundy came across Coz’s writing. When she read those words, she felt the all-encompassing magic in them. Immediately, she knew they’d be the epigraph of the book she was working on, Code Girls: The Untold Story of the American Women Code Breakers of World War II.

Over the past several years, Mundy relentlessly combed through archival records for her book. She pored over data, documents, and all there was to be read about the code girls, drawing from three large collections produced by the Army and Navy during and after the war. Most of these collections had been classified for decades. Now, many of the documents are available at the National Archives at College Park.

In her quest to tell the stories of the overlooked women who broke German and Japanese military codes, Mundy had to go through the National Security Agency, filing Mandatory Declassification Review requests. Her work resulted in the declassification of stacks of material pertinent to wartime women code breakers. With that and the archival collections, she found herself drowning in about 15 oral histories and hundreds of boxes that included “thousands of memos, internal histories, reports, minutes, and personnel rosters, citing everything from lists of merchant ships sunk, to explanations of how certain codes and ciphers were broken, to names and addresses of newly arrived code breakers, to captured codebooks,” she writes.

Mundy found that the recruitment letters women received set this history-making code-breaking in motion. The sinking of enemy ships during World War II had begun with simple letters. Mundy calls them Harry Potter letters: These women were finding out they could be wizards capable of great power, and they were receiving their invitations to schools of witchcraft and wizardry—the Army and Navy.

The letters first went out to elite women’s colleges in 1941, shortly before the attack on Pearl Harbor, inviting select women to interviews. The interviewers asked two very simple questions: “Do you like crossword puzzles and are you engaged to be married?” Answer the questions correctly—yes and no, respectively—and you made for a good candidate.

Through all of Mundy’s research, a portrait of these young women began to emerge. But her work was far from done. History hadn’t yet recognized the women’s integral part in shortening and winning the war. History had forgotten them.

So, she had to find them.

Mundy managed to track down and interview more than 20 of these code breakers, now in their 90s. She could tell some of the women were “fading,” but they still happily told her tales of what they could remember about that time in their lives, and the archives backed up their memories.


At the center of her book is Dot Braden, a Lynchburg native and former schoolteacher. Mundy had to convince her that it was no longer treasonous to talk about her secret work and accomplishments during the war. The punishment for treason during wartime was death. Navy code breaker Edith Reynolds White (middle) unwinds with colleagues.Courtesy of Edith Reynolds White

“The women were told that just because they were female, that did not mean they would not be shot if they told anybody what they were doing,” Mundy writes. Still, Braden feared the repercussions of talking about breaking enemy codes, even so many decades later. With the help of Braden’s son, who says he’d hardly ever heard his mother talk about her work, Mundy convinced her that it was permissible. For many of the surviving code breakers, Mundy was the first person they had ever talked to about their service.

In 1942, Braden was 22 years old and teaching six subjects to multiple grades in southern Virginia. The war had caused teaching shortages. She wanted to look for other work, and her mother mentioned that government recruiters had come to the Virginian Hotel looking for schoolteachers to do a mysterious job near D.C.

Braden had barely traveled and only on one occasion had ever left the state. She sprang for adventure, showing up to the hotel in September of 1943 to approach the recruiters. A few weeks later, a fateful letter came to her home. She was invited to work for the U.S. Army Signal Intelligence Service. She went to Arlington Hall in Arlington County, one of the base facilities for code-breaking, which still stands today.

Like the thousands of other recruits who ended up working there, Braden had no clue what she would be doing upon arrival. She soon found out that she was given one of the most paramount assignments in the building. She had to crack the codes of the ships bringing critical supplies to Japanese troops near the Pacific islands.

Arlington Hall itself has a special place in history. It was where some of the most significant code-breaking happened, and it was also home to a concealed African-American unit of mostly women that was totally segregated from, and unknown to, many of their white counterparts. Though Mundy searched and searched, she found few records about the unit and the contributions these African-American women made. But she did find out what their work entailed. They broke commercial codes, trying to find out which companies were doing business with Adolf Hitler and the Japanese corporation Mitsubishi.

Together, all of these code breakers were on the cutting edge of science, technology, engineering, and math. Their work mattered. They broke major Axis code systems. They tested America’s own codes for security. They sunk ships. They created “fake radio signals that helped fool the Germans into believing the D-Day invasion would take place in Norway or the Pas de Calais region of France—rather than on the beaches of Normandy,” Mundy writes.

They formed the foundations of government signals intelligence and cybersecurity. Of course, there are many reasons the Allies won the war. Not least in that bevy of reasons, though, are these women whose diligence saved lives. 

“They are entitled to glory and national gratitude which they will never receive,” said New York Representative Clarence Hancock of the code breakers in 1945 on the House floor following war victory.

Code Girls is about giving the code breakers the glory and gratitude to which they are entitled. Telling their individual narratives and their story as a whole, in all its tragedy, heartbreak, jubilation, and success, is Mundy’s way of thanking them for their service. In the bloodiest war in history, one with unprecedented loss and carnage, they quietly served their country as best they could.

Their names—Dot Braden, Jaenn Coz, and thousands more—aren’t etched into the victorious annals of American history. But then again, the names of those everyday people who wind up helping to change the course of the world never seem to be. Now, the women who signed their lives away are hidden figures no more.

Because of Mundy’s unearthing of their stories, they are getting more appreciation than they ever got at the time. During one of her interviews, a surviving former code breaker mentioned the small acknowledgment her commander gave one night after a code-breaking triumph. “Good job, girls. You did good. And that’s all he said.”