Recognized for its depth of research into history’s most powerful device of war, historian Richard Rhodes’ The Making of the Atomic Bomb (1987) documents the development of the atomic bomb in the 1930s and 1940s, from its conception to its deployment as part of an atrocity committed by the United States against Japan. Rhodes provides extensive background on the personal histories and scientific achievements of the group of international scientists who collectively brought the atomic bomb from a theoretical possibility into an implementable weapon. This process took place from its initial theoretical proposal in 1939, through the United States’ funding of a nuclear bomb program in 1941, and the successful tests and deployment of the bomb on Hiroshima in 1945.

The book begins with Rhodes’ assertion that the invention of the atomic bomb was a critical evolutionary moment in world history and international relations. He traces the concept of the “atom,” originally defined by the ancient Greeks as the most indivisible unit of matter, through its linguistic origin to the inception of the theory of nuclear fission and its potential as a weapon in 1933. At this time, a scientist named Leo Szilard was the first to state that fission could be harnessed as a destructive force. Originally from Hungary, Szilard studied under Albert Einstein, fleeing to Great Britain due to the Nazi persecution of Jews. Incensed by remarks at a scientific conference, he successfully worked to refute Ernest Rutherford’s claim that atomic power could never be harnessed as an energy source. Focusing his research on how to make nuclear fission net energy producing, he conceived of using neutrons to split the atomic nuclei of uranium in a self-sustaining chain reaction. However, due to an absence of financing, he was unable to implement his blueprint.

The next critical event in the timeline of the atomic bomb was the experimental demonstration of fission. In 1938, a German laboratory proved that atomic fission could be harnessed for power. Many scientists were immediately frightened that this technology was so close to the possession of Adolf Hitler; several prominent physicists fled central Europe to abdicate any potential role in helping him. At this time, Szilard and a physicist named Edward Teller sought to notify Franklin Roosevelt that the German danger was real and imminent. They drafted their warning into a letter and gained Einstein’s signature. It is unclear whether the President read the letter, given his delay in starting the American effort to create the atomic bomb that eventuated much later.

Meanwhile, the scientists in Germany were making consistent progress toward a working version, championed by Werner Heisenberg. They ultimately lost the race, and a bomb did not fall into Hitler’s hands, which Rhodes attributes to two primary factors: One was a flawed technical specification for the bomb that was never fixed. The other was German scientists’ anxiety to bolster the power of any of the unstable regimes that were gaining traction in the country; they felt that if a bomb got into the hands of a dictator, it would cause irreparable harm to the world. Japan had a parallel effort to create a bomb, but given its limited resources, projected that its invention was a full decade away.

Finally, in 1941, the United States began to take the invention of the atomic bomb seriously. Roosevelt contacted Winston Churchill in the fall of 1941 acknowledging that England was further along in the race and appealing to create a joint development effort. They went on to share information, giving both countries a leg up in the invention process. Also, at that time, Roosevelt appointed the people who would go on to found the Manhattan Project, the first official atomic bomb program. Not long after, Enrico Fermi accomplished the first proven sustainable chain atomic reaction in Chicago.

Rhodes continues to explicate the political consequences of the atomic bomb’s fruition. He gives credit to scientists’ collective effort to warn United States leaders about the inevitability of a nuclear arms race, arguing that it was one of the most significant preemptive measures taken to protect the safety of the globe. He also attributes the imperative for the fast development of the bomb to global paranoia that Germany would be first, a suspicion later shown to be invalid, as Germany made little progress. Finally, he explains that many of the scientists were ambivalent at best about the use of the bomb on Japan to stop World War II; most scientists were arguably in favor of its use to prevent what they believed would be a continually escalating host of atrocities. Szilard, one of the most horrified scientists, felt ashamed of his role in creating the technology. Yet, enough protections were put in place that the bomb was never used in war again after Hiroshima.

In his conclusion, Rhodes argues that the reconception of the modern nation-state was the primary force that accelerated the invention of the atomic bomb. Ultimately, he credits the scientific community as the primary ethical voice that halted the unchecked march toward destructive power. Thus, the book is both a historical study and the vindication of the ethical roles that scientists have played in shaping national and international policy.