x c i v A C K N O W L E D G M E N T S Castagnetti, Max Planck Institute for the History of Science, Berlin Michael Eckert, Sommerfeld Edition, Deutsches Museum, Munich Konstantinos Giapis, Caltech Stefanie Grunack, Geheimes Staatsarchiv Preussischer Kulturbesitz, Ber- lin Siegfried Grundmann, Berlin Hanoch Gutfreund, Hebrew University of Jeru- salem Claire Guttinger, Collège de France, Paris Klaus Hentschel, University of Stuttgart Herbert Karbach, Politisches Archiv des Auswärtigen Amtes, Berlin Waltraud and Miriam Kis, Vienna Annette Krebs, Bibliothek Exakte Wissenschaf- ten, Universität Bern Hans-Josef Küpper, Cologne Michaela Laichmann, Wiener Stadt- und Landesarchiv, Vienna Claudia Lienhard, ETH Library, Zurich Stefan Litt, National Library of Israel, Jerusalem Ad Maas, Museum Boerhaave, Leyden Mary Manning and Ryder Kouba, Special Collections, University of Houston Li- braries Rachel Misrati, National Library of Israel, Jerusalem Heleen Pronk, Am- sterdam Kerstin Schimmeck, Bundesarchiv, Berlin Kathleen E. Shoemaker, Man- uscripts, Archives, & Rare Book Library, Emory University, Atlanta Robert J. Schulmann, Bethesda, Md. Werner Strahalm, Stadtarchiv Graz Alfredo T. Tol- masquim, Instituto Brasileiro de Informação em Ciência e Tecnologia, Rio de Ja- neiro Yvonne Voegeli, ETH, Bern Dalila Wallé, Museum Boerhaave, Leyden. Charlotte Erwin, Judy Goodstein, and Loma Karklins of the Caltech Institute Archives have been generous in their help with archival documents and rare books. Intensive work has been carried out at the Einstein Papers Project by talented and dedicated students. We thank Mara Julseth, Lernik Ohanian, Claus Spenninger, and Thea Wade. Our activities and well-being at Caltech have been furthered by the assistance of Jonathan Katz, Tiffany Kim, Gail Nash, Ed Stolper, Candace Younger, and many other colleagues. We thank our longtime copy editor, Alice Calaprice, who has freelanced for us since retiring from Princeton University Press. Many thanks to everyone at Princeton University Press, especially to Linny Schenck, Terri O’Prey, and Leslie Flis, our production team Brigitta van Rhein- berg Neil Litt Adam Fortgang Martha Camp and Peter Dougherty, its director. We dedicate this volume to the memory of Reuven Yaron, notable legal scholar, who was instrumental in formulating the initial plans for the publication of the Ein- stein edition and served for many years on its editorial advisory board, and of Erwin N. Hiebert, distinguished scholar, who for many decades trained and in- spired generations of historians of science across several continents, and provided assistance to the editors since the inception of the series.