The editors have benefited greatly from many sources. We wish to thank The
Hebrew University of Jerusalem for granting us permission to publish materials
from its holdings. The ongoing support of Harold McGraw Jr. is deeply appreci-
ated. Support was also provided by Boston University and the California Institute
of Technology, as well as by the following European institutions: the Federal Insti-
tute of Technology (ETH) in Zurich, the Swiss National Science Foundation, and
the Dr. Tomalla Foundation in Liechtenstein.
We thank Ze’ev Rosenkranz, the Bern Dibner Curator of the Albert Einstein
Archives of the Jewish National and University Library at The Hebrew University,
and his assistants Dina Carter and Barbara Wolff for their generous cooperation.
We are grateful to Sybille Franks, Flavia Lanini, Rudolf Mumenthaler, and Yvonne
Vögeli of the ETH Library, Zurich, without whose assistance much of the docu-
mentation from Switzerland could not have been assembled; to Angela and Karl-
heinz Steinmüller of Berlin and Gelsenkirchen, who made German archival mate-
rial available to us; and to Max Markwalder and Hanni Hediger at the Photolab,
ETH Hönggerberg, Zurich, who prepared many of the facsimiles.
We thank John Stachel for his meticulous review of the manuscript; Marianne
de Laet and Henriette Schatz for the translation of Appendix D and other Dutch-
language material; and Fritz Stern, Martin J. Klein, Jed Z. Buchwald, and Issachar
Unna for comments on the final draft.
The assistance of the following persons in producing this volume is also grate-
fully acknowledged: Rhoda Bilansky and other members of the Interlibrary Loan
Office at Mugar Library of Boston University; Bing Lin Zhao, Boston University;
the staff of Boston Photo Imaging; Jobst Broelmann, Nautical Division, Deutsches
Museum, Munich; Adam Bryant and Rei Diaz for computer support; the diligent
staff of the Millikan Library, and the Institute Archives, at the California Institute
of Technology; Edward Doctoroff, Widener Library, Harvard University; Astrid M.
Eckert, Yale University; Michael Eckert and Karl Märker, Sommerfeld Edition,
Deutsches Museum, Munich; Margot Fuchs, Historical Archives, Technical Uni-
versity of Munich; Wilhelm Füßl and Eva Mayring, Archive of the Deutsches
Museum, Munich; Sammy Gergis, Boston University; Domenico Giulini and
Norbert Straumann, University of Zurich; Volker Häselbarth, Deutsche
A C K N O W L E D G M E N T S