Craig R. Gralley spent more than 30 years at the CIA, where he worked as a chief speechwriter for three agency directors: William Webster, Robert Gates, and R. James Woolsey Jr. When Gralley, now 62, retired from Langley in 2013, he began writing in the voice of someone quite different: legendary World War II spy Virginia Hall, a woman known as “The Limping Lady.”

For the past four years, Gralley, who still works as a part-time CIA contractor, has been researching Hall’s life for a book. Not a work of nonfiction, though. Two Hall biographies already exist, and another volume — along with a movie starring Daisy Ridley of “Star Wars” — is apparently  on the way.

Instead Gralley has written a novel, tentatively titled “Hall of Mirrors,” that he hopes to sell to a publisher. It’s narrated in the first-person, in the voice of Hall, who worked for the British in France during World War II and later became a CIA officer. The Maryland-born operative helped organize the French resistance against the Nazis and once fled the Gestapo by hiking through the Pyrenees on a wooden prosthetic leg she nicknamed Cuthbert.

At a time when few women worked as spies, Hall went on to work for the Office of the Strategic Services, the CIA’s precursor, and then the CIA itself before retiring at the age of 60 in 1966. She became such a celebrated figure at Langley that the agency named a training facility after her earlier this year called “The Virginia Hall Expeditionary Center.”

Although Gralley’s book is a piece of fiction, it is based on a surfeit of facts. He hiked Hall’s route through the Pyrenees and unearthed hundreds of documents related to her career from the National Archives in Britain, many of which have not circulated beyond the collection, he said.

He shared two records that have tantalized him the most: typed letters to Nicolas Boddington, a senior official at the Special Operations Executive, the British wartime spy service. (Multiple spellings of Boddington’s first and last name appear online.) These are not mere greetings, however. Gralley said Hall, a former code clerk for the U.S. Department of War, encrypted them.

She had to work as covertly as possible. By August 1941, she had established a headquarters in southern France and was passing along intelligence about the Vichy government and the underground resistance movement to her British spymasters. Armed with forged documents, she disguised herself as a New York Post reporter, according to an article Gralley wrote earlier this year for “Studies in Intelligence,” a CIA publication. All the while, she was cultivating a network of spies in France, supporting British agents with weapons and supplies, and offering safe houses to British operatives. Hall became so well-known that even the Gestapo’s chief, Klaus Barbie, known as the “Butcher of Lyon,” began hunting for her.

“My dear Nic,” she wrote on May 1, 1942 from her perch in Vichy France. “All things in series of three, as usual, a cold in the head, an ache in the thorax and mingled snow, rain and slush out of doors…The dark days are fairly abysmal and a short English word describes one’s mood….I have hoped for many days to go yodelling in the delightful, peaceful neighboring country, but alas for some bloody idiocy the usual keenness for new hotel guests is momentarily dampened by horrid suspicions which like an old fashioned detective story has tendencies toward complications lurid and even spectacular. Nerts, and nerts again! I get so ‘fed up.’ Queer, ain’t it?”

By early November, after their defeat in North Africa, the German forces swept into France’s free zones. Hall was convinced they would close down the borders. She knew she had to escape quickly, even if she was hobbled by Cuthbert, her seven-pound wooden leg, which she had relied on after a hunting accident. She teamed up with resistance members and left France on Nov. 11 to cross into the Pyrenees, seeking refuge in Spain. When she reached Spain a few days later, she got arrested for illegally crossing the border.

While she was incarcerated, Hall somehow managed to smuggle out another letter to Boddington — a letter Gralley said he believes she must have written in France before her trek through the Pyrenees. The letter is dated Nov. 25, 1942. Hall was still in a Spanish prison. She wasn’t freed until early December.

So how did Hall get the letter out from her cell?

“She might have been able to bribe someone,” Gralley said. “Also, her cellmate was a Spanish prostitute who got out before Hall’s release. She could have taken the letter to the U.S. or British consulate.”

Gralley suspects a British operative or agent likely typed up her letter after it was sneaked out.

Regardless, the note is mystifying, comically so. Several letters are circled and underlined. Those are the markings of British spy officials, Gralley said, searching for clues in the patterns of her words and letters.

“My dear Nic,” she wrote on Nov. 25, 1942. “You were probably as stunned as we by the news of Weygand’s departure. An event quickly arranged and greatly surprising the poor populace which thought that the tenacity of the umpire, I mean the chef d’Etat was no Kedegerris. Unfortunately the old fellow is not uninfluenced by all his horrid queezy ministers, although knowing that this beastly business of kowtowing means the quagmire for the country. Alas! there is however a new rumour, one which I can not check but on which I do not look haughtily. Strange things — you know — often do happen.”

Gralley said he believes both letters are encrypted to varying degrees. To help with the decoding, he’s emailed them to friends, retired cryptanalysts from the CIA and National Security Agency.

Hall was eventually released from prison. In the spring of 1944, she signed up with the OSS and worked her way back to France, now entirely occupied by the Nazis. While she was away, the OSS sent letters back to her mother, Barbara Hall, who was living outside Baltimore. Here, again, is where Gralley’s digging paid off. He came across a series of letters the OSS sent Hall’s mother, reassuring her of Hall’s safety, but omitting any frightening details.

“My dear Mrs. Hall,” a military official wrote on June 2, 1944. “From a security point of view there is little I am permitted to tell you about your daughter’s work. For this I am sorry; it may however be of some consolation to you to know that my own husband knows absolutely nothing of my work; and such is the case of the family of every soldier in our forces. But this I can tell you: that your daughter is with the 1st Experimental Detachment of the U.S. Army; that she is doing an important and time-consuming job which has necessitated a transfer from London, and which will reduce her correspondence to a minimum.”

A few months later, Hall’s mother received another letter.

“You must not worry, Mrs. Hall,” the official wrote on August. 23, 1944. “Virginia is doing a spectacular, man-sized job, and her progress is rapid  and sure. You have every reason to be proud of her.”

As a speechwriter, Gralley is accustomed to writing in the voices of others. He wrote a speech for Gates when the agency was displaying a piece of the Berlin Wall by one of the campus’s entrances. He crafted numerous speeches for the agency’s annual memorial ceremony that required him to research the lives of operatives killed in the line of duty.

“I got a chance to look at the files of the people who had been killed. It’s the toughest kind of speech to write but it’s the most important speech to write,” Gralley said. “You want to make sure you get it right.”

Gralley does not need to get every detail right for a work of fiction, though he certainly tried. The longtime CIA official, who lives in Great Falls, Va., began the novel three years ago after he enrolled in a creative writing master’s degree program at Johns Hopkins University. Mark Farrington, who served as the program’s assistant director, became Gralley’s thesis adviser, helping him shape the first draft at the Hall novel.

He wasn’t sure at times if he needed to step back and write about her in a nonfiction way, or whether it was okay to stick with her voice and tell her story,” Farrington said. Ultimately, he went with her voice.

Gralley said he approached writing from the perspective of a woman with great care. He selected a female professor for his final workshop at Hopkins and asked her and fellow female students to critique portions of his manuscript.

“They wouldn’t let me get away with anything that was less than authentic,” Gralley said.

He also modeled Hall based on his own observations of agency women who served in hazardous postings overseas.

“To be successful officers they have to be tough and confident,” he said. “That’s Virginia Hall.”

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