Spanning fifty years, "Before the Fall-Out" tells the full story of how an exhilarating quest to unravel the secrets of the material world produced the knowledge of how to destroy it. And of how a scientific adventure shared openly between nuclear physicists from many different nations transmuted into a secretive wartime race for the ultimate weapon of mass destruction - the atom bomb. As much as on the science, "Before the Fall-Out" focuses on the 'human chain reaction' - the intertwined lives of the many scientists of many nations whose compulsive curiosity led, however unwittingly, ultimately to Hiroshima. In her page-turning account Diana Preston reveals how individuals responded to events - from Allied scientists debating the morality of deploying the bomb, to Japanese civilians who became its first victims, and to a German chemist working on the Nazi bomb project while concealing a Jewish pianist in his Berlin apartment. Diana Preston draws on fresh material including interviews with the last living scientist to have worked with Marie Curie, the only senior scientist to have walked out on the Manhattan Project on moral grounds, and the German scientist who accompanied Werner Heisenberg on his controversial wartime visit to Niels Bohr in Copenhagen. A Manhattan Project scientist said that the only secret of the bomb was that it could be made: once this was known, any nation could replicate it. "Before the Fall-Out" helps us make better sense of our own, dangerous world and of the threats and moral dilemmas that face our society today.