I really enjoyed this historical novel set around the most closely guarded secret of WWII and the biggest scientific discovery of it's time. The tension between the sisters that causes Eleanor to abandon her dreams and take the job at the army base is told in flashbacks as Lillian is at the base posing as Eleanor to gain information. There was lots of mystery, cover ups and layers as Lillian tries to pose as her sister to figure it all out, not knowing who can be trusted, and not knowing exactly what is going on at this facility. Lots of twists and turns keep the story moving to it's conclusion and the revealing of the project. In the end it's a story that questions how some of the smartest scientists of the time could have justified the end results of a project in order to rise to the challenge of the project itself. I thought this was a great debut novel.