The editors have benefited greatly from the assistance of many individuals and
institutions. 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 appreciated. Generous
assistance was provided by the California Institute of Technology, and by its Virgle
L. Hedgcoth and Susan Alexander Fund. We thank Mrs. Lynda Hughes and the Sid-
ney Harman Family Foundation for generous gifts. We also thank the Swiss Federal
Institute of Technology in Zurich, which provided support for editorial work at
Caltech from 2002 to 2004.
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 Dr. Roni Grosz of the Albert Einstein Archives of the Jewish National
and University Library at The Hebrew University of Jerusalem for their sustained
assistance and generous cooperation.
Heinrich Wanner, representing the Heinrich Zangger Erbengemeinschaft of Zur-
ich, was kind enough to give us access to his grandfather’s Nachlass in the Special
Collections at the Central Library of Zurich. Christoph Eggenberger, the director
of Special Collections there, and his colleagues Ruth Haeusler, Angelika Hugger,
and especially Gabriele Wohlgemuth were extremely helpful.
We thank the members of the Executive Committee for much helpful advice.
Issachar Unna, of The Hebrew University, has provided his expertise in carefully
reading the manuscript. We gratefully acknowledge editorial work and annotation
carried out on some documents contained in this volume by Robert Schulmann.
Rosy Meiron of Caltech has assisted in proofreading.
We are particularly indebted to Shady Peyvan, Judy Nollar, and the rest of the
dedicated staff of the Millikan Library and the Institute Archives at Caltech who
have tracked down hard-to-find sources and information.
Much historical information and detail were needed in the research and produc-
tion of this volume. We are grateful to Rudolf Mumenthaler, Yvonne Vögeli,
Sybille Franks, and Flavia Lanini of the Swiss Federal Institute of Technology’s
library, and to Gian Andrea Nogler and Hanspeter Stucki of the University of