“We’ve had astronauts, we’ve had engineers—John Glenn, Gene Kranz, Chris Kraft,” she says. “Those guys have all told their stories.” Now it’s the women’s turn.

The West Computers were at the heart of the center’s advancements. They worked through equations that described every function of the plane, running the numbers often with no sense of the greater mission of the project. They contributed to the ever-changing design of a menagerie of wartime flying machines, making them faster, safer, more aerodynamic. Eventually their stellar work allowed some to leave the computing pool for specific projects—Christine Darden worked to advance supersonic flight, Katherine Johnson calculated the trajectories for the Mercury and Apollo missions. NASA dissolved the remaining few human computers in the 1970s as the technological advances made their roles obsolete.

The first black computers didn’t set foot at Langley until the 1940s. Though the pressing needs of war were great, racial discrimination remained strong and few jobs existed for African-Americans, regardless of gender. That was until 1941 when A. Philip Randolph, pioneering civil rights activist, proposed a march on Washington, D.C., to draw attention to the continued injustices of racial discrimination. With the threat of 100,000 people swarming to the Capitol, President Franklin D. Roosevelt issued Executive Order 8802, preventing racial discrimination in hiring for federal and war-related work. This order also cleared the way for the black computers, slide rule in hand, to make their way into NACA history.

Exactly how many women computers worked at NACA (and later NASA) over the years is still unknown. One 1992 study estimated the total topped several hundred but other estimates, including Shetterly’s own intuition, says that number is in the thousands.

As a child, Shetterly knew these brilliant mathematicians as her girl scout troop leaders, Sunday school teachers, next-door neighbors and as parents of schoolmates. Her father worked at Langley as well, starting in 1964 as an engineering intern and becoming a well-respected climate scientist. “They were just part of a vibrant community of people, and everybody had their jobs,” she says. “And those were their jobs. Working at NASA Langley.”

Surrounded by the West Computers and other academics, it took decades for Shetterly to realize the magnitude of the women’s work. “It wasn’t until my husband, who was not from Hampton, was listening to my dad talk about some of these women and the things that they have done that I realized,” she says. “That way is not necessarily the norm”

The spark of curiosity ignited, Shetterly began researching these women. Unlike the male engineers, few of these women were acknowledged in academic publications or for their work on various projects. Even more problematic was that the careers of the West Computers were often more fleeting than those of the white men. Social customs of the era dictated that as soon as marriage or children arrived, these women would retire to become full-time homemakers, Shetterly explains. Many only remained at Langley for a few years.

But the more Shetterly dug, the more computers she discovered. “My investigation became more like an obsession,” she writes in the book. “I would walk any trail if it meant finding a trace of one of the computers at its end.”

She scoured telephone directories, local newspapers, employee newsletters and the NASA archives to add to her growing list of names. She also chased down stray memos, obituaries, wedding announcements and more for any hint at the richness of these women’s lives. “It was a lot of connecting the dots,” she says.

“I get emails all the time from people whose grandmothers or mothers worked there,” she says. “Just today I got an email from a woman asking if I was still searching for computers. [She] had worked at Langley from July 1951 through August 1957.”

Langley was not just a laboratory of science and engineering; “in many ways, it was a racial relations laboratory, a gender relations laboratory,” Shetterly says. The researchers came from across America. Many came from parts of the country sympathetic to the nascent Civil Rights Movement, says Shetterly, and backed the progressive ideals of expanded freedoms for black citizens and women.

Read more: The True Story of “Hidden Figures,” the Forgotten Women Who Helped Win the Space Race