PUBLISHER'S FOREWORD Albert Einstein died on April 18, 1955. His will, dated March 18, 1950, reads: I give and bequeath all of my manuscripts, copyrights, publication rights, royalties and royalty agreements, and all other literary property and rights, of any and every kind or nature whatsoever, to my Trustees hereinafter named.... The will then, at some length, specifies that the Trustees shall have full power "to sell, publish, license or otherwise dispose of any or all of the said property and rights...." It names "my friend, Dr. Otto Nathan" as sole executor of the Estate, and further designates Otto Nathan and Helen Dukas as joint Trustees. The will also provides that ultimately all rights shall pass to The Hebrew University of Jerusalem. Professor Einstein could not have chosen a more dedicated executor and trustee than Dr. Nathan, nor could he have specified a more knowledgeable and devoted trustee than Miss Dukas, who had been his secretary since 1928. Dr. Nathan immediately set about gathering, organizing, and administering the many and complex copyrights, contracts, and other business matters pertaining to the Einstein papers. Miss Dukas served as archivist, making the papers available to qualified scholars, writing explanatory notes to be inserted in the files, and helping Dr. Nathan in an extensive search for all Einstein-related documents, including correspondence. Thus, through their efforts, many documents were preserved that might otherwise have been lost, and the archive grew. At the time of Professor Einstein's death he had one scientific paper in the process of publication, "Relativistic Theory of the Non-symmetric Field." It appeared on March 5, 1956, as Appendix C of his book The Meaning of Relativity, which Princeton University Press had originally published in 1923. Thus Princeton is both the first and the last American publisher of Einstein's work in his lifetime. The thought that Einstein's papers should be published was an obvious one. There was particular interest in the idea of publishing his scientific writings, as proposed after Einstein's death by Princeton University Press and