book review

Unearthing another set of amazing hidden figures

A team of women code breakers working for the US Navy during World War II.
A team of women code breakers working for the US Navy during World War II.National Archives and Records

After the bloody combat of World War II came to a close, Congress made a point of thanking cryptographers — the top-secret cadre of code breakers tasked with deciphering enemy secrets — for helping to end the war. The group had been invisible during the conflict but was, one congressman declared, as important as “any other group of men” in securing the allied victory.

“That more than half of these ‘cryptographers’ were women was nowhere mentioned,” notes Liza Mundy, in “Code Girls,’’ her detailed, fascinating, and sometimes infuriating book, which does much to close that gap in military history. Near the book’s end, she makes a point of thanking those unacknowledged heroes, admitting that the gratitude comes late, as most “took the secret [of their wartime work] to their graves.”


For the most part, though, disparities and discrimination are not so much called out as woven through the story’s fabric; Mundy’s focus is on her addictively readable story of behind-the-scenes efforts to discover enemy plans and safeguard soldiers and sailors on the battlefront. But it’s worth noting that her intent — to give credit to the unsung young women who helped save those lives — brings the book into a growing catalogue of recent works that shed light on the forgotten women of math and science.

Perhaps the best known of these is Margot Lee Shetterly’s best-seller “Hidden Figures’’ (2016), the story of a group of African-American female mathematicians who did some of the essential calculations for NASA space missions in the mid-20th century and who received no public acknowledgment for their accomplishments. (Shetterly’s tale also became an Oscar-nominated film of the same year.) The unsung work of women for the country’s space program is also illuminated in Nathalia Holt’s “Rise of the Rocket Girls’’ (2016).

And there are others: Dava Sobel’s “The Glass Universe’’ (2016) details the work of a group of influential and long-invisible women astronomers at Harvard University and Denise Kiernan’s “The Girls of Atomic City’’ (2013) explores the unheralded contribution of women in the creation of nuclear bombs in World War II.


The past few years have also seen a number of new titles dedicated to calling attention to the importance and lives of women in research, including “Headstrong: 52 Women Who Changed Science — And the World’’ (2015) by Rachel Swaby, “Women in Science: Fifty Fearless Pioneers Who Changed the World’’ (2016) by Rachel Ignotofsky, and “Lab Girl’’ by Hope Jahren (2016).

The realization that women’s scientific achievements have long been denied full credit is not a 21st century discovery; in the 1990s, the pattern was even given a name — “the Matilda effect” — by social scientist Margaret Rossiter. But at this particular time, when diversity in science is recognized as essential to a well-rounded research enterprise, when a new emphasis is being placed on role models for young women in such important fields, the subject has clearly — and let’s argue, thankfully — gained both attention and energy. There’s a feedback loop to making people invisible in history: It diminishes their importance, and reinforces stereotypes, such as the idea that certain groups might lack the ability or intelligence to thrive in challenging fields. In 2005, for instance, then-Harvard University president Larry Summers raised the possibility that “innate” aptitude might be one of the reasons women are not as dominant in science as men.


The books I’ve cited use evidence rather than polemic to counter Summer’s suggestion. Collectively, they arrive at another conclusion: that women’s failure to achieve scientific visibility results, at least in part, from being deliberately shuffled to the side. Group portraits, such as “Code Girls,’’ or individual ones such as Brenda Maddox’s award-winning book, “Rosalind Franklin: The Dark Lady of DNA’’ (2002), provide an inarguable pattern. They remind us that women have been vitally important to the success of both science and technology — if only we will give them that credit. They remind us that role models are available for the asking, if we are willing to look.

As Mundy notes, that influential women code breakers worked during World War II was largely because the profession was neither new nor noteworthy: “This lack of renown or formal regulation . . . created a wide crack through which women could enter.” And also because they had unique abilities. Deciphering codes requires an analytical, math-savvy mind, and an undaunted sense of intellectual inquiry. Some of the 20-something women in the story are downright brilliant in their ability to stare down a code puzzle. But they are also funny, family-oriented, friendly — a wonderful mix of youthful light-heartedness and dedication to the fight. Mundy, whose previous book credits include a biography of Michelle Obama, displays a gift for creating both human portraits and intensely satisfying scenes.

One of my favorite of these moments involves a desperate effort early in the war to decipher a complex diplomatic code used by the Japanese, shifted constantly by a cypher machine. As the fall of 1940 approached, American analysts had been working on it for months without success. On a warm September afternoon, a quiet young woman named Genevieve Grotjan, a former railway annuity statistician, nervously approached the men running the unit, “holding her worksheets clutched to her chest.” She laid the sheets down on the table and began circling a pattern of letters: “The men knew instantly what they were looking at. Grotjan had given them their entering wedge. While she stood quietly, they erupted in cheers.”


Beginning with Grotjan’s insight, the Americans were able to reverse engineer the Japanese machine and decipher an astonishing array of messages throughout the war. The discovery, unfortunately, didn’t allow them to foresee Pearl Harbor the following year. This was a diplomatic code, and the diplomats had been carefully excluded from those plans. But as the war continued, teams assembled by the Army and the Navy unraveled military codes as well, learning details as fine as the daily schedule of the Japanese planner of Pearl Harbor — which would lead to his plane being shot out of the sky by American bombers. By the war’s end, said one of the Army officers overseeing the effort, “There wasn’t a damn thing that the Japanese transmitted that we weren’t able to read.”

Similar work helped crack the codes used by Germany — and allowed American military strategists into what the Germans were decoding as well. That knowledge was used to create a web of fake information before D-Day, the Allied invasion at Normandy on June 6, 1944, which diverted a sizeable number of German troops to false targets. The women involved in that effort worked in complete secrecy, bolstered by the hope that their efforts would save lives. “Even seated at our desks,” one wrote later, “we felt the power of our country.”


In the end, Mundy’s story is one of women and men, bound together by their wish to serve the country, working side by side as equals, temporary but real. And in that picture is more than a marvel of patriotic effort. It’s a reminder that side-by-side as equals is who we are at our best — and how we do our best.


The Untold Story of the American Women Code Breakers of World War II

By Liza Mundy

Hatchette, 416 pp., illustrated, $28

Deborah Blum is the author of three history of science books, most recently “The Poisoner’s Handbook,’’ and director of the Knight Science Journalism Program at MIT.