Thomas Powers in the New York Review of Books:
Almost as soon as World War II ended in Europe, and with redoubled intensity after the bombing of Hiroshima, physicists all over the world began to ask how close the Germans had come to making an atomic bomb. But it was not clear whom to ask. Everything to do with development of the bomb was cloaked in secrecy and ten of the leading scientists involved in German atomic research had gone missing. One of them, Otto Hahn, the first to explain the fission process that made bombs possible, was on November 15, 1945, awarded the Nobel Prize in chemistry for his discovery, but the prize committee, it turned out, had no idea where Hahn was.
Among the few who did know were leading scientists who had developed the American bomb at Los Alamos in New Mexico. Many of them were Jews by Nazi standards who had fled Hitler’s Germany, including the physicists Hans Bethe and Victor Weisskopf, who had feared at the beginning of the war that the great German theoretical physicist Werner Heisenberg would build a bomb for Hitler. In 1942, learning that Heisenberg was going to give a scientific talk in Zurich, Bethe and Weisskopf had proposed an American operation to kidnap Heisenberg in Switzerland and even offered to take part themselves. This episode, improbable as it sounds, has been well documented elsewhere and after many twists and turns the original proposal led to Heisenberg’s detention in southern Germany in May 1945.