Albert Einstein"s first tour of America was an extravaganza unique in the history of science, and indeed would have been remarkable for any realm; a grand two-month processional in the spring of 1921 that evoked the sort of mass frenzy and press adulation that would thrill a touring rock star. Einstein had recently burst into global stardom when observations performed during a total eclipse dramatically confirmed his theory of relativity by showing that the sun"s gravity field bent a light beam to the degree that he had predicted. So when he arrived in New York in April, he was greeted by adoring throngs as the world"s first scientific celebrity, one who also happened to be a gentle icon of humanist values and a living patron saint for Jews. Newly published papers from that year, however, show a less joyful aspect to Einstein"s famous visit. He found himself caught in a battle between ardent European Zionists and the more polished and cautious potentates of American Jewry. The full extent of this controversy, which has been only touched upon in previous books(including a biography I wrote in 2007), is revealed in a volume of Einstein"s correspondence and papers for 1921 that was recently published by the Princeton University Press. Einstein was raised in a secular German-Jewish household, and(except for a brief fling with religious fervor as a child)he disdained religious faith and rituals. He did, however, proudly consider himself Jewish by heritage and he felt a strong kinship with what he called his fellow tribesmen or clansmen. His outlook in 1921 can be seen in the brusque answer he sent early that year to the rabbi of Berlin, who had urged him to become a dues-paying member of the Jewish religious community there. "In your letter, " he responded, "I noticed that the word Jewish is ambiguous in that it refers CD to nationality and origin, (2)to the faith. I am a Jew in the first sense, not in the second. " German anti-Semitism was on the rise. Many Jews did everything they could, including converting to Christianity, in order to assimilate, and they urged Einstein to do the same. But Einstein took the opposite approach. He began to identify even more strongly with his Jewish heritage, and he embraced the Zionist goal of promoting a Jewish homeland in Palestine. In addition to papers, the book published by the Princeton University also includes