 Includes a previously unpublished manuscript on relativity and electrodynamics, a notebook documenting his preparation for his first joint paper (1913, with Marcel Grossmann), previously unknown calculations with Michele Besso on the motion of the perihelion of Mercury, etc.Includes more than five hundred previously unpublished letters to and from Einstein in his early adulthood, from his first employment at the Swiss patent office in 1902 through his appointment to the Prussian Academy of Sciences in 1914.Correspondents included Max von Laue, Paul Ehrenfest, Alfred Kleiner, Fritz Haber, Walther Nernst, etc.