""I have done a lot of work on the history of mathematicians living in the first half of twentieth century. I edited correspondence between André Weil and Henri Cartan. I have also written about the way the Jews were forbidden to publish in France during the German occupation. I found some correspondence between two mathematicians at the time of the occupation. One was French, a collaborationist, and the other one German, a member of the army. In their letters, they were very friendly and exchanged very pro-Nazi opinions. I hoped to publish this correspondence, but then I realized the family would never give permission.Even now, not everybody in France is willing to publicize the fact that he or she had relatives who, seventy-five years ago, collaborated with the Germans. This is one thing that led me to write the novel. When you say, “So-and-so was French and became a German collaborator,” or “this was a bad guy, and that was a good guy”—you are just making an accusation. That was quite the opposite of what I wanted to do. I wanted to have a different kind of freedom, to write something that was not academic research. I wanted to have something more—how to do I say this (very modestly!)?—something more universal. I wanted to write in a different way from a standard paper in history or mathematics and to reach different kinds of readers. Of course, the main reason was that I wanted to write a novel,"."