Einstein was one of the great conceptual revisers of humankind's understanding of the universe. Born of Jewish parents, he was educated in Munich, Arau, and Zurich. He took Swiss nationality in 1901, was appointed examiner at the Swiss Patent Office from 1902 to 1905, and began to publish original papers on the theoretical aspects of problems in physics. He achieved world fame from his special and general theories of relativity in 1905 and 1916, and won the Nobel prize in physics in 1921. By 1930 his best work was complete. After Hitler's rise to power, he left Germany and from 1934 lectured at Princeton University, becoming an American citizen and professor at Princeton in 1940. In September of 1939, he wrote to President Roosevelt warning him of the possibility that Germany would try to make an atomic bomb, thus helping to initiate the Allied attempt dubbed the Manhattan Project. After the war he urged international control of atomic weapons and protested against the proceedings of the un-American Activities Senate Subcommittee which had arraigned many scientists. He spent the rest of his life trying, by means of a unified field theory, to establish a merger between quantum theory and his general theory of relativity, thus bringing subatomic phenomena and large-scale physical phenomena under one set of determinate laws. His attempt was not successful. However, today as in the year Einstein died, the prospect for a grand, unified theory is as elusive as ever.