In their introductory meetings, the chosen women were issued manila envelopes containing a brief introduction to the arcane history of codes and ciphers, along with numbered problem sets and strips of paper with the letters of the alphabet printed on them. They were to complete the problem sets every week and turn them in. They might help one another, working in groups of two and three. Each week, professors such as Helen Dodson, selected by the Navy, would lead the students through the material. Their answers would be sent to Washington and graded. The meetings functioned as a kind of proctored correspondence course. Speed was of the essence, and often the professors were little more than a chapter ahead of the students in learning the material.
And so the young women did their strange new homework. They learned which letters of the English language occur with the greatest frequency; which letters often travel together in pairs, like s and t; which travel in triplets, like est and ing and ive, or in packs of four, like tion. They studied terms like “route transposition” and “cipher alphabets” and “polyalphabetic substitution cipher.” They mastered the Vigenère square, a method of disguising letters using a tabular method dating back to the Renaissance. They learned about things called the Playfair and Wheatstone ciphers. They pulled strips of paper through holes cut in cardboard. They strung quilts across their rooms so that roommates who had not been invited to take the secret course could not see what they were up to. They hid homework under desk blotters. They did not use the term “code breaking” outside the confines of the weekly meetings, not even to friends taking the same course.
The summons spread beyond the Northeast. Goucher, a four-year women’s college in Baltimore, Maryland, was known for the caliber of its science departments. Goucher’s dean, Dorothy Stimson, a noted authority on Copernicus, happened to be a cousin of Secretary of War Henry Stimson. After Pearl Harbor, the war secretary put in a quiet word, asking for some of Dean Stimson’s best senior girls. At Goucher, it was an English professor—Ola Winslow, awarded a Pulitzer Prize for her biography of the American theologian Jonathan Edwards—who was selected to teach the secret course, once a week, in a locked room at the top of Goucher Hall, together with a Navy officer.
Goucher was located in the heart of urban Baltimore. The U.S. Naval Academy was thirty-two miles away in Annapolis, and “Goucher girls,” as they were called, traveled there often for dates and dances.
One of the most well-liked students in the Goucher class of 1942 was Frances Steen, a biology major and the granddaughter of a shipping captain who ferried grain between the United States and his native Norway, which now was under Nazi occupation, its king compelled to leave the country under fire. Her father ran a grain warehouse at the Baltimore dock. Her brother, Egil, had graduated from the Naval Academy, and by the time Fran got her own secret letter, Egil Steen was on North Atlantic convoy duty. The Steen family was doing everything they could to support the war effort. Her mother was saving grease from bacon, giving away pots and pans to be made into tanks and guns.
Now, it appeared, there was something else the Steen family could contribute to preserve their son’s safety: Fran.
As war engulfed the nation, the summonses continued to go out. Even after Pearl Harbor’s shock receded, secret letters were sent again, in 1942, 1943, and 1944, as code breaking proved crucial to disrupting enemy operations and saving Allied lives. At Vassar, nestled in the hills of Poughkeepsie, New York, Edith Reynolds received a letter inviting her to appear in a room in the library at nine thirty a.m. on a Saturday. Edith was barely twenty. She had skipped two grades in elementary school and entered Vassar when she was just sixteen years old.
The letter invited Edith to a room in the college library, where she stood, dazzled, as a hulking Navy captain walked in, covered top to toe, it seemed to her, in the most magnificent gold braid. “Your country needs you, young ladies,” he told Edith and a few chosen classmates.
By the time Edith got her summons, German U-boats had attacked shipping up and down the Atlantic coast. On the New Jersey shore, where her family spent summers, bits of shipwreck would wash up and they could hear guns booming. It did not seem out of the question that Japan would invade the U.S. mainland—Alaska, even California—or that America would come under fascist domination.
The U.S. Army, meanwhile, needed its own cadre of code breakers and set out to recruit apt young women. At first, the Army approached some of the same colleges the Navy did, prompting angry memos from top Navy brass, bitterly upset that the Army was “cutting in” to try to get their girls. Like the Navy, the Army wanted women who were college educated—ideally women who had pursued a rigorous liberal arts education that encompassed foreign languages as well as science and math. In the United States, in the 1940s, there was really only one job consistently available to a woman with such a fine education: schoolteacher.
And so—while the starchy, white-gloved Navy officers targeted the fancy women’s colleges of the Northeastern Seaboard—the U.S. Army sent recruiters to teaching colleges, far humbler institutions, throughout the South and Midwest. At Indiana State Teachers College in Indiana, Pennsylvania, Dorothy Ramale was taking high-level math classes in the hope of becoming a math teacher. Dorothy had grown up in rural Pennsylvania—a tiny place called Cochran’s Mills, known, if it was known at all, for being the birthplace of Nellie Bly. The middle of three girls, Dorothy used to sit on the porch of their playhouse and dream about the world beyond. It was Dorothy’s ambition to see every continent on earth. As a child, her only contact with the wider world came from rare events like the time when Amelia Earhart flew over a local cemetery to salute a relative who was buried there, and Dorothy, along with other schoolchildren, waved as the legendary aviatrix passed overhead.
Dorothy’s father had supported his family through the Depression by farming and doing maintenance at a church cemetery. People sometimes asked if he regretted not having a son to help him, and he was quick to retort that his three girls were as good as any boy. Dorothy helped him with stacking hay and other outdoor chores, sometimes crawling down into a freshly dug grave to retrieve a tool he needed. At college, she often was the only girl in her trigonometry classes. Math was not a subject women were encouraged to study, and certain parts of the country had no female math teachers at all. Dorothy knew the odds, but math was her passion.
During her senior year, Dorothy stayed up late one night in February and went out to watch as her male classmates were put on a bus and sent to Pittsburgh to begin their military service. She could hardly see them through her tears. Afterward, the campus felt lonely and awful. When the dean of women invited her in for a quiet talk, she instantly agreed to do what the dean was proposing.