Ann Hagedorn
Simon and Schuster, 2021

Reviewer: Nuclear Physicist and Advisor to CIA and FBI Dr. Les Paldy

Ann Hagedorn's Sleeper Agent is a masterfully researched account of one of the most successful Soviet spies in American history–George Koval. A gifted young chemist and a native-born American, Koval infiltrated the heart of the Manhattan Project, passing critical nuclear weapon secrets to the Soviet Union during World War II. Unlike Klaus Fuchs and other Soviet operatives who were eventually exposed, Koval's espionage went undetected for decades, making his story even more remarkable.

Hagedorn's meticulous research brings to life a spy who operated in plain sight, his ideological convictions driving him rather than monetary gain. As she explores Koval's path—from his upbringing in an immigrant Jewish community in Iowa, his family's emigration to the Soviet Union in1932 in response to antisemitism and prejudice in the U.S., to his Soviet training and eventual placement in the Manhattan Project-the book also explores his worldview and motivations.

The book provides a concise overview of the history of the time, touching on the immigration of European physicists to the US, the first experiments with nuclear fission at Columbia University, the Einstein letter to President Roosevelt, and the decision to organize the Manhattan Project. It also describes Soviet tradecraft for handling Koval.

One of the book's most compelling aspects is its exploration of Koval's lasting impact.

The information he transmitted to the Soviet Union on the production of polonium for nuclear weapon triggers probably contributed to the Soviets achieving nuclear parity far earlier than U.S. officials had anticipated, detonating their first nuclear weapon in 1949.

Yet, despite the significance of his espionage, Koval never wavered in his belief that he had done the right thing, seeing his actions as maintaining a global balance rather than an act of betrayal.

Hagedorn also raises intriguing questions about modern intelligence and counterintelligence. Koval's success was facilitated by an era in which deep background hecks relied on paper trails rather than digital footprints. Today, a spy with his history— someone who had lectured and written in support of Communist causes—would likely be flagged early in the vetting process through simple internet searches. His ability to penetrate the most secretive scientific endeavor of the 20th century seems almost inconceivable in the digital age.

For readers interested in Cold War espionage, nuclear history, or the Manhattan Project's security vulnerabilities, Sleeper Agent is a fascinating read. It is both a biography of an enigmatic spy and a cautionary tale about the ways in which ideology, espionage, and historical circumstances can align to shape world events.

Dr. Lester Paldy, a nuclear physicist and professor at the State University of New York at Stony Brook, played an advisory and operational support role for CIA and FBI for 25 years. Paldy, an AFIO member and regular contributor to The Intelligencer, last year published a memoir about his exploits as a scientist working in the U.S. intelligence community: No Cloak, No Dagger: A Professor’s Secret Life Inside the CIA (Rowman and Littlefield, March 2024).