In August 1939 Albert Einstein signed a letter to President Franklin Roosevelt, warning of the potential of Adolf Hitler’s Nazi regime to use uranium to develop an atomic bomb. “The most important source of uranium,” he added, was in Africa—in the Belgian Congo (now the Democratic Republic of Congo). It was therefore a priority for the U.S. to build its own bomb and to secure all available Congolese ore. But there was a risk that uranium might be smuggled out of the Belgian colony to Germany. To prevent this, the Office of Strategic Services, America’s new intelligence service and forerunner of the CIA, established a station in the Congo. The station’s agents included a courageous woman named Shirley Chidsey, one of the small number of women OSS agents to serve overseas.

Shirley Chidsey, born Elinor Shirley Stewart, was in her mid-thirties when she first went to Africa. Her features were plain, but she had an intelligent, independent, and lively air, which made her almost beautiful. OSS files record that she had grey eyes, brown hair, a fair complexion, and petite build: just five foot one inch tall, weighing 52 kg. Her father died when she was little and when her mother married again, she was given his surname of Armitage. She grew up in a gracious home in Swarthmore, Pennsylvania, where her family frequently appeared in the society pages. But Shirley wanted more out of her life than a busy calendar with the smart set. She studied in New York at Barnard College and then at Columbia University, taking “numerous writing and lit. courses,” as well as French.

Shirley had a huge appetite for travel and adventure. She lived for three years in Haiti, three months in Hawaii, a month in France, and a month in Germany, and visited China. In 1935 she married the author Donald Barr Chidsey and went with him to Tahiti, where she sailed in his boat and helped to manage a coconut plantation; she also learned Tahitian. While there she made friends with a number of writers, including F. Scott Fitzgerald. Tahiti has often been described as paradise, but the same could not be said of the Chidseys’ marriage: Shirley separated from him in February 1940. She went to New York and placed an advertisement in the Saturday Review of Literature for a “Girl Friday”—to do typing, research, and stenography.

When the U.S. entered the war, she joined the Office of Strategic Services in New York as a stenographer in French. As a woman, she was in a minority in OSS, which was dominated by men and male attitudes. The Ivy League universities that most of them had attended “were all male, and the OSS was very heavily so.” One agent, Elizabeth MacDonald, wrote a memoir after the war entitled Undercover Girl, which describes the sexism of the organization. “Women have no place in the war,” one colonel told her dismissively. “All the time I’ve put in overseas—and that’s four years—I’ve only come across one who was worth her salt.” When General William Donovan, the head of OSS, gave instructions about the “right types” of women to be hired, one definition of right type was a Smith graduate who could pass a filing exam. Most of the 26,000 women who joined OSS worked in the secretarial field and only a small percentage—some 700—served overseas.

These attitudes held women back. But Chidsey was eager to serve overseas and when an opportunity came up in French Equatorial Africa in 1943, she jumped at it, though it meant leaving OSS. The post was that of transcriber at Radio Brazzaville, a radio transmitter beaming propaganda on behalf of Free France. This, thought Chidsey, would be an ideal way of doing her bit for the war.

But she was unhappy in Brazzaville and wondered if it might have been better to join the Women’s Army Auxiliary Corps. “Rather wish,” she mused with feeling to her mother, “I had joined the WAACS tho’ and perhaps got to North Africa with them.” It was not all bad news though. “But I did have one nice thing happen,” she reported home. “I had dinner with a handsome naval officer and sat on his terrace overlooking the Congo and saw the full moon rise big & red out of the dark river and had a tall whisky and soda …”

Then another nice—but far more significant—thing happened: she was able to return to OSS. But this time, it was to work not in the New York office, but in the OSS station in Léopoldville (now Kinshasa), the capital of the Belgian Congo. In Brazzaville she had met Dock Hogue, the OSS chief of station in Léopoldville, on the opposite side of the Congo River. Thirty-four years old and just short of six feet three, Hogue was athletic and strikingly good-looking, with a narrow moustache. A sombre and very clever civil engineer, he nursed a dream of becoming an author. But for now, he was carrying out a top secret mission for his country: keeping Congolese uranium out of the hands of the Axis powers. His cover was the investigation of diamond smuggling and his codename was TETON.

Hogue and Chidsey had much to talk about, including their shared interest in literature. They were also both isolated and lonely. Shirley told Dock about her “urgent desire to escape Brazzaville” and her “extremely disagreeable living and working conditions.” He suggested that she cross the river to Léopoldville, to become his assistant. No doubt he felt sorry for her. But he was also overburdened with work and she seemed ideal: she spoke French fluently and had even worked previously for OSS.

Hogue asked Rud Boulton, the head of the Africa Section in Secret Intelligence at OSS headquarters in Washington, for permission to hire Chidsey. It was vital that he had “a loyal and competent person” he could trust, he pointed out, since he was the only OSS representative in the Congo. It was essential, he argued, that the secretary in Léopoldville be herself “of ‘agent stature’ … [and] she must have complete loyalty to OSS and the proper feeling for the security of operations.”

Boulton was impressed by Chidsey’s record and in December 1943 he initiated a security check and sent some inquiries. A question about sports and hobbies elicited an arch response: “None particularly.” When asked if she had ever used intoxicants, she responded: “The usual ‘occasional cocktail.’” By late January 1944, she had been cleared to work for the Africa Section of OSS. Her codename would be ANGELLA and her codenumber would be 1080.

The OSS station was transformed by Chidsey. It had been over nine months since Hogue had first arrived in the Congo—a period of intense difficulty, sickness, and excessive travel, in the context of harsh colonial racism and severe inequities. But he no longer had to worry about leaving the office unattended and, in addition, ANGELLA was adept at cultivating informants and information. Hogue was proud of the information he and Chidsey sent to Washington. “How does our little office stack up for volume?” he inquired. “I won’t ask about quality,” he commented with his usual self-effacing humor, “because that is always a problem.”

Chidsey was also good company—a smart, kind, and funny woman, with unusual hobbies—she was an enthusiastic railfan and avid reader of Railroad Magazine, a journal devoted to trains. This interest was useful, given the importance of the Congo’s vast rail networks to the export of uranium ore to America.

In July 1944 Hogue and Chidsey were joined by Henry Stehli, a sophisticated but easygoing man whose cover was his role in the family business—the famous Stehli Silks Corporation; his codename was LOCUST. The OSS station appeared to be growing steadily. But just days before Stehli’s arrival, Hogue’s cover was unexpectedly blown open, putting him in danger of his life. He was also vulnerable as a result of information he had gathered about collaboration between businessmen and senior policemen in the Belgian Congo with the Nazis.

Realizing he may have to escape at any moment, Hogue prepared to hand the station over to Stehli. “ANGELLA knows pretty well what our files contain, and can be of assistance in this respect,” he told him. “Her memory is excellent regarding names of persons on whom we have dossiers, and can save you a lot of time.” But he was concerned about her. If she were to leave the Congo, she would need a flight with Air Transport Command, which was extremely difficult for women. “After six months service with us,” he hoped, “she should be made eligible for ATC transportation to the United States … I personally feel that her services merit this consideration.” Her work, he said, was very good: “ANGELLA has tapped a mine of information in Poskin, the news editor of L’Avenir Colonial Belge.” So, he added with self-mocking humor, “except for the Chief who can’t stay out of trouble, things are going along pretty well.”

Hogue survived two threats on his life. But when he was attacked by a gunman in his bedroom at home, he immediately implemented his plan for escape. Stehli took over, relying on ANGELLA as “a loyal and trusted agent.” But he became very ill: a thin and exhausted shadow, who had no choice but to leave the Congo in April 1945.

This meant that Shirley Chidsey became de facto chief of station. She was now based in the U.S. Consulate and sending reports to OSS. “1080,” noted Boulton in Washington with evident approval, “is developing rapidly into a competent source during this interim period.”

***

After Germany surrendered in May 1945, there was no longer any reason to fear a German atomic bomb and, in any case, Nazi Germany had failed to build one. Leading German physicists attributed this failure to the lack of uranium ore, which can be considered a tribute to the clandestine OSS mission in the Congo. OSS operations in Africa were now being reduced, but the station in the Congo was maintained. In June 1945, a senior OSS official flew to the Congo to arrange cable communications for ANGELLA. There were now “1 secretary at the Léopoldville station, 4 informants regularly used, and 1 undercover agent.”

But in September, OSS representation ceased in the Congo too, “with the official closing of the Congo office by 1080,” who left Africa. Very shortly afterwards, President Truman abolished OSS.

Chidsey returned to the Congo in January 1946 to work for the U.S. consul. Boulton arranged with the State Department for her to send reports back to the Central Intelligence Group, which had replaced OSS. “Anything you hear from me so far,” she wrote to Boulton, “is completely unofficial and unsponsored. I shall keep it up to whatever extent seems practicable, and meanwhile keep a sort of background file which will be ours … Best to you all, and I miss hearing from you.”

Shirley Chidsey finally left the Congo in September 1947. She became editorial assistant on Railroad Magazine and then worked on literary projects as an editor, including a translation of The Pillow Book by Sei Shōnagon. She remarried, taking the surname Bridgwater. Neither she, Hogue, nor Stehli received any recognition of any kind for their brave contribution to the fight against fascism.

Excerpted from Spies in the Congo: America’s Atomic Mission in World War II by Susan Williams. Copyright © 2016. Available from PublicAffairs, an imprint of Perseus Books, LLC, a subsidiary of Hachette Book Group, Inc.

Dr. Susan Williams is a senior fellow in the School of Advanced Study, University of London. Her recent books include Who Killed Hammarskjöld?, which triggered a new UN investigation in 2015, and Colour Bar, now a major film entitled A United Kingdom.