James Franck (1882-1964) was a renowned, Nobel Prize-winning director of a world-class physics institute when the National Socialists came to power. For half a century he had lived as a Jew among the Germans, and for three decades he had worked as a German among the world's scientists. His life changed irrevocably when in April 1933 he publicly resigned his university position in political protest against the policies of the new regime.

Yet in another important sense, the patterns of a lifetime could not and did not change overnight. The characteristics of personality and intellect that had made Franck so successful were not shattered. If anything, they were further fused in the crucible of dramatic change. Yet in being applied to new conditions they faced unexpected challenges. Here lies one value of the biographical approach, for the mixture of stability and instability in the life of a single person underscores the complexity of emigration at every scale of analysis.

One of the striking aspects of Franck's life was his frequent role as a mediator across social and disciplinary boundaries, especially those of German-Jewish identity and of theoretical-experimental styles of scientific research. It was not that he stood on one side reaching out to the other, but that he positioned himself in the midst of complex interactions and reached out to both sides. He was therefore accustomed to tuning his hearing to the differing vocabularies and values among his friends, acquaintances, students, co-workers, and peers. He was also accustomed to shifting his position constructively in response to the mainstream of activity around him. Both habits were to stand him in excellent stead when he was forced to depart Germany.