Pointing to the way the Soviet nuclear program was structured, Gordin questions whether Soviet spies and captured German scientists made as much of a difference to the timing of the Soviet atomic bomb project as is often assumed. He focuses on the background to the first Soviet nuclear test, in August 1949, and how it was that the Americans were able to detect the test and then announce it before Moscow did. But Gordin undermines his research with a basic error on the second page, when he suggests that Winston Churchill was present at the Potsdam Conference in only an advisory capacity because he was no longer prime minister. In fact, he was prime minister -- until the results of the general election were announced, at which point he left the conference and his successor, Clement Attlee, took over. Fortunately, Gordin shows a surer touch with the material more central to his thesis, and his book is an interesting contribution to the literature on the origins of the nuclear arms race.