Harold W. McGraw, Jr. Virgle L. Hedgcoth & Susan Alexander Fund, California Institute of Technology The Hebrew University of Jerusalem and Princeton University Press wish to express their appreciation to the Contributors for their generous support of the editorial work that has made this edition of The Collected Papers of Albert Einstein possible. The California Institute of Technology, Pasadena, California, U.S.A. The National Endowment for the Humanities, Washington, D.C., U.S.A. The National Science Foundation, Arlington, Virginia, U.S.A. The Arcadia Fund, U.K. ENDOWMENT CONTRIBUTORS