A translation of The Collected Papers of Albert Einstein is being published by Princeton University Press, under the supervision of Diana Kormos Buchwald, General Editor. The translation of Volume 14, containing selected texts, was prepared by Ann Hentschel and Jennifer Nollar James. Klaus Hentschel was the consultant, and Alice Calaprice was the copy editor. At the Einstein Papers Project, Osik Moses and Emily de Araujo assisted with typesetting József Illy and Dennis Lehmkuhl assisted with the translation Diana Kormos Buchwald prepared the index and finalized the volume, and, together with Rudy Hirschmann, produced camera-ready copy. The translation volumes, produced in paperback, are intended to be read in conjunction with the documentary edition, as they contain none of the editorial commentary. NOTE ON THE TRANSLATION