This volume, the first in the series to be devoted to Einstein's
correspondence, begins in June 1902, when he went to work at the Swiss
Patent Office. It closes in March 1914, as Einstein left Switzerland to
take up his appointment as a member of the Prussian Academy of Sciences
in Berlin. The great majority of the more than 500 letters from and to
Einstein presented here have not been published before, and some of them
will be new even to most Einstein scholars. They give us a much richer
picture of Einstein in his twenties and early thirties than we have ever
had. We see him through his correspondence with his mother, his wife
Mileva, and, from 1912 on, his cousin Elsa, who would later become his
second wife. He maintains close ties with old friends, but his circle
widens, particularly after 1906, to include a number of his
contemporaries in physics such as Max Laue and Paul Ehrenfest. He also
develops important relationships with older theorists--Max Planck,
Arnold Sommerfeld, and especially H. A. Lorentz.
The letters in this volume clarify the development of his academic
career once he leaves the Patent Office in 1909, and bring out the
important parts played by such staunch supporters of Einstein as Alfred
Kleiner, Fritz Haber, and, above all, Walther Nernst.
Most significant, however, is the way the letters document crucial
aspects of Einstein's scientific activity: his concentration for years
on the unfathomable problems of quanta and radiation, his extensive
knowledge of experimental physics, his many fruitful interactions with
experimentalists, and finally his long struggle to generalize the 1905
theory of relativity to include gravitation and accelerated frames of
reference.
