A picture taken in Princeton, New Jersey, in August 1950 shows Albert Einstein standing next to the Austrian logician Kurt Gödel. Both men are looking at the camera. Einstein is wearing a rumpled shirt and baggy slacks held up by suspenders. His body sags. Gödel, dressed in a white linen suit and wearing owlish spectacles, looks lean and almost elegant, the austerity of his expression softened by an odd sensuality that plays over the lower half of his face. The men are at ease; they are indulging the photographer. Clearly, they are friends. It is hardly surprising that they should have come to know each other. They were members of the Institute for Advanced Study at Princeton, and their offices were close. As refugees from the Third Reich, they had both felt the harsh breath of history and had in common the rich, throaty German language, a world of words in which the pivot of memory turns on Goethe, not Shakespeare. Although Einstein was a physicist and Gödel a mathematician, they shared an intellectual daring that transcended their disciplines.