When the Fat Man atomic bomb exploded over Nagasaki on August 9, 1945, Dr. Takashi Nagai was working at a university hospital near ground zero. Barely escaping the dilapidated building and despite serious injuries, he and other doctors began treating survivors.

His account of the first terrifying days after the bombing formed the basis of his book, The Bell of Nagasaki. Dr. Nagai died of leukemia two years after its publication. His essay became a unique eyewitness account of the disaster, a scientist's reflection on the nature of the atomic bomb, and a humanitarian plea: something like this must never happen again.