Correspondence; note and memorandum books; lecture notes; annotated reprints; miscellaneous manuscripts; and academic and military records. Primarily correspondence, the collection documents in detail Schwarzschild's professional and personal life, reflecting many of the social, political, and scientific currents of his day. It consists predominantly of incoming letters from ca. 870 correspondents. Letters from astronomers document the history of late 19th and early 20th century astronomy; those from physicists (including 47 letters from Arnold Sommerfeld) reflect the early history of quantum theory, spectroscopy, and relativity. Correspondence with his family provides valuable insights into the history of science, the German academic community, and German Jewry. Notebooks (1891-1916) contain diary entries; drawings; student exercises in language, mathematics, and astronomy; travel notes; book lists; notes on reading; detailed astronomical observations; and calculations. Lectures (1893-1909) include material on celestial mechanics, mathematical physics, number theory, astrophysics, military tactics, and notes from Schwarzschild's pioneering 1904 lectures on astrophysics taken by Max Born. Also includes published articles on both scientific and popular topics with annotations; academic awards; military records; appointment books and a diary (1916) by his wife Else Rosenbach Schwarzschild; and memoirs of his brother Alfred. Correspondents include: L. Bauer, W. Biltz, O. Birck, O. Blumenthal, L. de Ball, R. Emden, M. Friedlander, E. Fuld, B. Gombrich, K. Gombrich, B. Guanenti, Ejnar Hertzsprung, L. Kapteyn, Felix Klein, E. Maier, G. Mller, D. Oppenheim, H. Seeliger, F. Wilke-Dorfurt, and C. Wirtz; also Schwarzschild and Rosenbach family members.