Reviewed by: Polonium in the Playhouse: The Manhattan Project’s Secret Chemistry Work in Dayton, Ohio by Linda Carrick Thomas Gregory Wilson Polonium in the Playhouse: The Manhattan Project’s Secret Chemistry Work in Dayton, Ohio. By Linda Carrick Thomas. (Columbus: Trillium, an imprint of Ohio State University Press, 2017. 247 pp. Cloth $29.95, ISBN 978-0-8142-1338-4.) Those familiar with the Manhattan Project are likely to know some of the significant people and places involved. Names such as Robert Oppenheimer [End Page 122] or Leslie Groves perhaps, and sites such as Hanford, Oak Ridge, and Los Alamos. Less widely known are the many other men, women, and places critical to the creation of the world’s first atomic weapons. In her book Polonium in the Playhouse, author and journalist Linda Carrick Thomas reveals the important role of the men and women in Dayton, Ohio, who performed secret chemistry work for the bombs, particularly her grandfather, Charles Allen Thomas. The book fills an important gap in the knowledge of the project and highlights the importance of not only of Dayton and Thomas but also of Ohio more generally to the history of World War II. The sense of scale—both small and large—as well as the technical complexity, tension, and drama associated with working at a feverish pace to create an atomic weapon come through in the book, as do some of the personalities. When the Manhattan Project got under way in 1943, Oppenheimer envisioned a relatively small chemical department in Los Alamos to work out the needed processes for the weapons. It became apparent rather quickly that the necessary chemistry would require a much larger undertaking, as the project expanded into a massive industrial operation that spread out across the nation, with an ultimate price tag of $2 billion. At the urging of Oppenheimer and Groves, Charles Thomas eventually took on supervision of the chemical operations and metallurgy required. He had the needed background, connections, personality, and skill for the job. By 1935, he and coworker Carroll “Ted” Hochwalt’s Dayton company, Thomas & Hochwalt Laboratories, was the nation’s largest independent consulting lab. Monsanto, its largest client, then bought out the company in 1936 and Thomas became director of research. He would eventually become president of Monsanto in 1951. He became part of the National Defense Resources Committee in 1940; Monsanto also would obtain several government contracts during World War II, particularly for synthetic rubber, and Thomas became further involved in government war administration. The author notes that her grandfather was “known for having good people skills and could bridge the gap between the project director and the scientists” (49). Thomas managed several assignments for the Manhattan Project, spread out across the United States. He coordinated plutonium chemistry and metallurgy at the University of Chicago’s Metallurgy Lab, UC Berkeley’s Radiation Lab, Los Alamos, and the uranium work at Iowa State University in Ames. Oppenheimer and Groves repeatedly pushed him to relocate to Los Alamos, but Thomas refused and coordinated his work from Dayton. In Dayton, he oversaw polonium purification at the Monsanto facilities in [End Page 123] the city, centered at the Playhouse, a large recreation building on his wife’s family’s former estate, Runnymede, that the government leased. Polonium became a key ingredient in initiating the chain reaction for a weapon involving plutonium. The author details the precise and complicated technical work conducted by and the day-to-day activities of the men and women at the Playhouse, as well as other locations in Dayton that were part of the secret program. This includes George Koval, a health inspector who was a spy funneling information to the Soviets, a fact only revealed after Koval’s death in 2006. Because the author had access to family records and stories, as well as government documents and other sources, she was able to provide information others may not have been able to. Along with technical and bureaucratic details of the story, readers will appreciate the author’s effort to showcase personalities, especially Thomas’s (with his singing ability and humor), and how workers had to navigate their daily lives while employed on a secret...