“The Girls of Atomic City: The Untold Story of the Women Who Helped Win World War II” by Denise Kiernan (Touchstone Books, $27)

Now in their 80s and 90s, the girls of Atomic City are no longer in the dark about the jobs they took during the summer of 1943. But back then, as young employees of the Clinton Engineering Works, they knew only a few things for sure about the place they would call home for the next two years.

Security was paramount: “Appropriate clearances had to be earned, physicals passed, photographs and fingerprints taken, urine collected, and stacks of ‘I swear I won’t talk’ papers signed.”

None of them had the faintest idea that they had signed on with the Manhattan Project and that their job was to collectively enrich the uranium that would be used in the atomic bomb.

In her meticulously researched and entertaining “The Girls of Atomic City,” Denise Kiernan explores this little known phase of the project’s history through the experiences of several young women who lived and worked in what would one day be known as Oak Ridge, Tenn.

“The Girls of Atomic City” brings to light a forgotten chapter in our history that combines a vivid, novelistic story with often troubling science. We’re left wondering how many would have refused the jobs had they known what the morning of Aug. 6, 1945, would bring.