The papers from 1921 show how, over the course of the year, Einstein morphed from physicist to celebrity. He remained a working scientist—in 1921 he was absorbed in attempts to unify gravity and electromagnetism—and continued to do serious theoretical work until his death in 1955, but the special theory of relativity, from 1905, and the general theory, from 1915, were both behind him. It was in 1921 that Einstein first traveled from his Berlin home to Europe as well as to America, spending just over six months on the road. The purpose of the American trip was to raise funds for a Hebrew University in what was then Palestine, but he also delivered 17 lectures on his then-controversial theory of relativity, including four at Princeton. He joined a campaign to raise money for Zionism, led by Chaim Weizmann (who would become Israel's first president), and sparred with physicists including Niels Bohr and Paul Ehrenfest about quantum theory—a man of physics and, equally, of world politics.

As the latter, he seemed to wrestle with his feelings about Germany, declining repeated invitations to visit Munich in the wake of World War I, but also traveling to Amsterdam to intervene on Germany's behalf at the Paris conference where the Allies met to determine how much Germany would pay in war reparations. He met with British Prime Minister Lloyd George and the Archbishop of Canterbury, and he discovered the cost of celebrity: the first published call for his assassination appeared in a right-wing German newspaper. (It was prompted by Einstein's membership in a pacifist organization called Neues Vaterland which issued a declaration, published on Jan. 2, 1921, criticizing Germany for not disarming more quickly and calling on France to be on guard against renewed German militarism and, if necessary, to intervene.)

Einstein's identification with Jewish causes also brought him enemies. He explained his 1921 fundraising for a Hebrew University as a way to help "persecuted and morally oppressed" fellow Jews, and said he had seen "innumerable" cases of "perfidious and loveless" handling of "splendid young Jews" denied entrance to and positions in universities. Because of his trip, Einstein was criticized by Nobel-winning chemist Fritz Haber, who invented chemical warfare and supervised its use by Germany in World War I, for traveling with "English supporters" of Zionism, an act Haber considered disloyal to Germany.

The documents in this new volume also contains the first reference to what would become one of Einstein's signature sayings. While still in Princeton, Einstein received news of preliminary experiments conducted at Mount Wilson, which seemed to find evidence for the effect of an ether—whose existence had been disproved by Michelson-Morley 33 years before. His reaction, as overheard by Princeton mathematician Oswald Veblen: "Subtle is the Lord, but malicious He is not."

© 2009