The editors have benefited greatly from the assistance of many individuals and
institutions. We extend our thanks to the members of the Executive Committee, and
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 appreciated. Generous
assistance was provided by the provost’s office at the California Institute of Tech-
nology, and by its Virgle L. Hedgcoth and Susan Alexander Fund. We thank Dr.
Lisbeth Rausing, Dr. Peter Baldwin, Dr. Fay Bound Alberti and the Arcadia Fund
for their interest and generosity in supporting our work. Many thanks also to the
Pieter Zeeman Foundation in Amsterdam.
We owe profound thanks to Barbara Wolff for her dedicated and meticulous
assistance in proofreading numerous documents in this volume, as well as to Chaya
Becker and director Roni Grosz at the Albert Einstein Archives at The Hebrew Uni-
versity in Jerusalem for their sustained assistance and generous cooperation. Fritz
Stern, John D. Norton, Issachar Unna, and Robert Schulmann have provided
invaluable expertise in carefully reading and evaluating the manuscript.
At Caltech, we are particularly indebted to Shady Peyvan, Judy Nollar, Sandy
Gerstang, and the rest of the dedicated staff of Millikan Library for tracking down
hard-to-find materials, and also to Bonnie Ludt, Charlotte Erwin, and Judy Good-
stein at the Institute Archives. Thanks to Brenda Shorkend, who has uncovered
numerous significant materials. We also thank the staff of the Swiss Federal Insti-
tute of Technology Library, the University of Zurich Archive, and the Special Col-
lections at the Zurich Stadtarchiv for their continued assistance in examining Ein-
Much historical information and detail were needed in the research and produc-
tion of this volume. The assistance of the following persons is gratefully acknowl-
edged: Brigitta Arden, Archives of Scientific Philosophy, University of Pittsburgh;
David Baneke, Leiden Observatory; Heinrich Berg, Wiener Stadt- und Landesar-
chiv; Joseph Braunbeck, Vienna; Jobst Broelmann, Deutsches Museum, Munich;
Wendy Chmielewski, Swarthmore College, Peace Collection; Christopher Dens-
more, Friends Historical Library, Swarthmore College; Esther Dreifuss-Kattan,