By Denise Kiernan

Touchstone, $27; 320 pp.

Imagine a city of more than 70,000 people hidden in plain sight. In 1942, the United States government decided to build just such a city in the hinderlands of Tennessee. It was to be the site of massive plants that would help build the secret weapon that the government hoped would speed the end of World War II.

They chose a site back in the hills, 83,000 acres nestled between ridges near the small towns of Kingston, Tenn., and Clinton, Tenn. It was a sparsely settled area, home to only a few communities with names like Wheat, Elza and Robertsville. All those little places would disappear, absorbed into the larger place that was called “Clinton Engineering Works” or “Kingston Demolition Range” or “Site X” or just “the Project.” Thousands of people would eventually work there, their endeavors shrouded in secrecy as they labored to produce something called “the product” that would be used in “the gadget.” Only a handful knew what was really going on: the product was enriched uranium and the gadget was the first atomic bomb.

Using eyewitness accounts, Kiernan tells the story of the secret city that was made in the city surrounded by a fence, a place that eventually became the town of Oak Ridge, Tenn. Headed by Gen. Leslie Groves of the Army Corps of Engineers, a whole town was constructed with streets, housing and, most importantly, the huge plants with cryptic alphanumeric names: K-25, Y-12, X-10, K-27, S-50. A massive amount of materials went into the construction but as locals often observed, “Everything’s goin’ in and nothin’s comin’ out.”

In order to staff the huge plants, recruiters were sent out across the South and the East. So many men were off in the service that labor was in short supply. Women were their first choice.

“The Project liked high school girls, especially those from rural backgrounds. Recruiters sought them out relentlessly, feeling young women easy to instruct. They did what they were told. They weren’t overly curious. If you tell a young woman of 18 from a small-town background to do something, she’ll do it no questions asked. Educated women and men, people who had gone to college and learned just enough to think that they might ‘know’ something, gave you problems. The Project scoured the countryside of Tennessee and beyond looking for recent graduates.”

Kiernan uses the voices of some of those women to paint a portrait of life in the vacuum of secrecy that was imposed on Oak Ridge during World War II. There’s Celia Szapka, a secretary from Pennsylvania who started in the Project’s New York office. Virginia Spivey, a chemist from North Carolina, was one of the rare college-educated women in Oak Ridge. Dorothy Jones from Hornbeak, Tenn., was a calutron operator who watched gauges and adjusted knobs to help enrich uranium electromagnetically, but who had no idea what she was doing. Colleen Rowan, was a “leak inspector” at K-25, and she had no idea what was in the pipes she tended. Toni Peters was a secretary from nearby Clinton, Tenn., whose Yankee boss often made fun of her East Tennessee accent. Jane Greer, a statistician-mathematician from Paris, Tenn., kept an eye on production rates at Y-12. The words of these five and four other women who worked at Oak Ridge are alternated with chapters describing the evolution of the atomic bomb, the physics behind it and the brilliant processes by which the uranium needed was enriched and processed at Oak Ridge then assembled into a bomb at Los Alamos, N.M.

The women describe living conditions, the early “hutments,” crude tent housing, the advent of cemesto (a mix of concrete and cement) houses that, in military fashion, were dubbed “A,” “B,” or “C” houses according to their size. There were no sidewalks, and they all battled sticky red clay mud in the winter and summer. Most weren’t allowed to cook in their tents or hutments and had to eat in a cafeteria, although not all ate together; the black workers were segregated.

Through the story of Alabaman Kattie Strickland, Kiernan shows how black people were discriminated against even in government projects led by the most-highly educated people of the time. Kattie lived in one hutment, her husband in another. Black couples were not allowed to cohabitate, even if they had a license to prove their marriage.

Kiernan also explores the friction between all the outsiders brought in to man the plants in Oak Ridge and the locals who often resented their presence — they weren’t welcome in some stores in Knoxville, she writes. It wasn’t just simple prejudice, Kiernan explains, but stemmed from the way the government obtained the land for Oak Ridge.

“The Taking encompassed large tracts of land and small farms, ramshackle hovels, and expansive homesteads, hills with memories, crops, and orchards. A man named Van Gilder lost 1,000 acres. The Brummitt family was promised $900 for 40 acres and did not receive all of it. The Irwin family was offered $10,500 for their Gamble Valley farm, which included a large antebellum home, a five-room framed house, two tenant houses, barns, outbuildings, crops, and equipment. The amount offered could not buy half of what was ‘bought’ from them. Entire communities and the ways of life that infused them were to be wiped away in a matter of weeks.”

It was hard for locals to accept, and no one was telling them why it had to be that way.

Eventually, the atomic bomb was built and dropped on Japan, ending the war. Everyone was grateful for the role Oak Ridge had played in ending the war and finally understood the necessity for all the secrecy, the privations and the confiscations. Still, the legacy of secrecy persisted as the world entered the Cold War era. Much of Oak Ridge’s wonderful World War II story remains untold, hidden in classified documents. Kiernan uses research, interviews, maps and photos to craft what is probably the best account of the Secret City yet written. It’s certainly timely. As she points out, the last living veterans of the Project are rapidly disappearing and with them the best sources of Oak Ridge’s history.