The Collected Papers of Albert Einstein. Vol. 12 Correspondence, January-December 1921 : Princeton University Press : 9780691141909 : 0691141908 : 03 Jul 2009 : In this latest volume, Einstein's visible public persona is amply documented in his correspondence, honors and prizes, lectures and travels, articles, and the many solicitations asking him to join public initiatives. Einstein joins a Zionist fundraising mission led by Ch. Weizmann, and he visits the United States for the first time. Einstein travels to major cities, including New York, Boston, and Chicago, and he delivers his now famous Princeton Lectures. Scientific issues remain at the core of Einstein's preoccupations. Correspondence with N. Bohr, W. Bothe, P. Ehrenfest, H. Geiger, H. A. Lorentz, L. Meitner, and A. Sommerfeld records Einstein's interest in and contributions to the emerging modern quantum theory. He addresses conceptual problems, such as the fundamental nature of light and its emission mechanism, in a propo