When Army Air Forces officer Claude Eatherly piloted the plane Straight Flush in support of Enola Gay ’s mission to obliterate the city of Hiroshima, his tasks were little different from those of past flights. It was just another flight requiring the twenty-six-year-old’s technical acumen, but it also involved wiping 70,000 people off the face of the earth. Eatherly would later feel anguish over his role: He repeatedly attempted suicide and was eventually institutionalized. At the time, though, he saw it as just another job.

How had this convergence of routine activity and unprecedented catastrophe become possible, and what did it mean? For the philosopher Günther Anders, this was the defining question of the twentieth century, and of the final epoch of man that he saw unfolding around him.…