Operation Paperclip examines how the US government recruited Nazi scientists after World War II while concealing their backgrounds from the public. The titular Operation Paperclip was a postwar intelligence initiative that brought German scientists to America on classified military contracts. The book focuses on 21 of the more than 1,600 German technologists who transitioned from serving Hitler’s regime to working for the United States.

Established in May 1945, Operation Paperclip enabled scientists who had supported the Third Reich’s military campaigns to continue developing rockets, chemical and biological weapons, aviation medicine, and other armaments. Employing committed Nazis, Jacobsen argues, represented an unprecedented departure from American principles. Undersecretary of War Robert Patterson acknowledged the fundamental problem when debating program approval, noting that these men were enemies.

The scientists profiled were deeply embedded in the Nazi apparatus. Eight collaborated directly with Hitler, Himmler, or Göring; 15 held Nazi Party membership; 10 joined the paramilitary SA or SS; two received the Golden Party Badge signifying Hitler’s personal favor; and one earned a 1-million Reichsmark award. Six faced Nuremberg trials; one was convicted of mass murder and enslavement, yet later hired by the Department of Energy after serving prison time and receiving clemency.

The Joint Intelligence Objectives Agency (JIOA), operating from the Pentagon’s elite “E” ring, recruited Nazi scientists for weapons projects across the Army, Navy, Air Force, and eventually the CIA.