x c v i i i E D I T O R I A L M E T H O D Interviews that contain substantial blocks of quotations by Einstein are placed in an appendix. All available letters written by Einstein or written to Einstein are presented either in full text, or as an abstract in the Calendar of Abstracts. Letters addressed to more than one recipient are presented only once. Authors and dates of known but unavailable letters are cited if only an excerpt of a significant original letter is available, it is printed in full. Einstein became director of the Kaiser Wilhelm Institute of Physics (KWIP) in October 1917, and his correspondence in that capacity is substantial. Unless they are of particular significance for the understanding of Einstein’s deliberations or actions, all letters to and from Einstein in his capacity as member of the board of directors (Direktorium) of the KWIP, or from him to the board of trustees (Kurato- rium) and to other members of the board of directors of the KWIP, as well as all third-party documentation of his role as director of the KWIP, are abstracted in the Calendar, as are routine financial and administrative exchanges with Einstein, grant applications, and correspondence with publishers and translators. Einstein’s postscripts that serve only to extend greetings, have no independent character, or are appended to letters by other authors, are abstracted in the Calendar. On occasion, certain documents, such as appeals, petitions, statements, certifi- cates, and official reports, as well as third-party letters that are important for under- standing Einstein’s development, milieu, and public activities, are printed in whole, in part, or in summary. After the series of documents pertaining to Einstein’s Berlin years is finished, any remaining undated documents and fragments that can be dated only to an ap- proximate span of several years within the period 1914–1932 will be published to- gether as supplementary volumes. These will be followed by a new chronological series covering the Princeton years, 1933–1955. ESTABLISHMENT OF TEXTS It is our general policy to work initially from a photocopy or digital scan of a man- uscript or typewritten text, and then to perfect our transcription against the original, if available. If neither the original nor a photocopy is available, we base our text on a previously transcribed or printed version. If more than one such version is avail- able, we select the one that in our opinion agrees most closely with features char- acteristic of the author’s style, orthography, and punctuation, departing from the text only to correct unambiguous typographical errors.