I N T R O D U C T I O N T O V O L U M E 1 3 x x x v Japan, Einstein completed a paper that further developed Eddington’s point of view by supplementing it with field equations to determine the connection’s coefficients derived from a variational principle. Both in his writings and in the correspondence presented here, a certain sense of restlessness and awareness of change constitutes a recurring theme. There is no doubt that Einstein wished to escape the demands attendant on his growing fame and visibility. He tried to decline some of the numerous invitations to lecture, argu- ing, with little success, that he had nothing new to say, and insisting that he would only speak on advanced scientific topics and to specialist audiences (see, e.g., Doc. 219). But he understood that “the wider public, and politics, have long since taken control of my theory, and my person, and have tried somehow to adapt both to their own purposes” (Doc. 63). The 415 letters presented as full texts were selected from among a total of 980 incoming and outgoing items of correspondence. They reflect Einstein’s scientific preoccupations, as shown in the intense correspondence with Paul Ehrenfest and exchanges with other physicists and with mathematicians, philosophers, adminis- trators, and international organizations and journals. Most significant is his corre- spondence with representatives of the French scientific community, where he expresses his sincere desire to contribute actively to mending the frayed, or even nonexisting, scientific relations among former enemy nations. In this spirit, con- flicted and buffeted by external events, he vacillated when asked to participate in the International Committee on Intellectual Cooperation of the League of Nations. Rathenau’s assassination deeply affected Einstein. Not for the first time, but cer- tainly with a feeling of greater urgency, Einstein wanted to leave Berlin, now a life- threatening place, with its attendant social obligations, scientific meetings, and administrative burdens. He seriously contemplated leaving the Prussian Academy of Sciences, and academic life altogether, and envisaged for a while the possibility of moving to Kiel. He contemplated there a secluded, rural, but luxurious lifestyle made possible through work in the factory owned by the entrepreneur and inventor Hermann Anschütz-Kaempfe, with whom he had a long-standing collaboration. In all the external turmoil, Einstein yearned for a “normal” life (see Doc. 276). Others, too, offered Einstein refuge from Berlin. In the wake of rumors that he was about to leave Germany because of anti-Semitism, Einstein was invited to take up residence in Italy and was confidentially offered a professorial appointment, au- thorized by the Italian minister of public instruction (Doc. 428). Nicholas M. But- ler, president of Columbia University, and his colleagues also offered him a professorship, and the assurance that America is “a quieter place than Germany” (Doc. 432). In a similar vein, he was extended “Spain’s hospitality and the financial support of the government in case the current conditions in his homeland should