These excerpts were brought together by Slater from his files, at the request of Dr. Leon Rosenfeld, to document Slater's visit to Copenhagen, and Bohr's Lab. In general, the letters concern quantum physics.

These contain a few notes and memoranda by Van Vleck, but the bulk of the collection is letters to and from him. Correspondents include Raymond T. Birge, Gerhard H. Dieke, Paul A. M. Dirac, Edwin C. Kemble, and Robert S. Mulliken.

These are copies of material, mainly letters, not filmed for the Archive for the History of Quantum Physics (see PAAV86-A21). There is an interesting letter from Charle G. Darwin (1932) referring to Paul Ehrenfest, letters about the state of physics at Northwestern University from R. A. Fisher and B. J. Spence, and a letter by Hermann Weyl outlining a talk he was to give in Boston in December 1928.

This collection includes numerous Darwin writings, in manuscript and typescript, as well as letters to him from Niels Bohr, Max Born, M. Frenkel, Oskar Klein, J. E. Littlewood, H. Moseley, H. R. Robinson. The writings include such topics as magnetic storms, atom mechanics, and wave theory. There is also a copy of a paper in Darwin's hand by Henri Poincaré, "On the theory of Quanta" (published in Journal de Physique, 1912).

John Archibald Wheeler (1911-2008) was a leading theoretical physicist of the twentieth century, contributing particularly to the fields of general relativity, gravitation, and quantum mechanics. Wheeler was a pioneer in the study of black holes, celestial phenomena which he named. (He had a penchant for creating new terms in physics, and is credited with naming other phenomena such as geons, wormholes, and quantum foam.) Wheeler is also known for his work in atomic and nuclear physics. In 1939, he and Niels Bohr co-authored a paper that gave the basis for recognizing that Uranium 235 and Plutonium 239 are highly fissile, a milestone in the understanding of atomic energy. Wheeler believed in the importance of public service, assisting in the U.S. war effort to develop the atomic and hydrogen bombs, and served as a scientific advisor to numerous government agencies. During a prolific academic career that spanned seventy years, Wheeler taught physics to thousands of undergraduate students at Princeton University and the University of Texas, and mentored more than fifty Ph.D. students. The Wheeler Papers provide an extensive look into the expansive career of John Archibald Wheeler, the pioneering and award-winning theoretical physicist. Comprised of 150 linear feet, this large collection contains a wide array of materials including correspondence, subject files, manuscripts by Wheeler, papers by colleagues and students, research notes and notebooks, photographs, awards, and audiovisual materials. The collection provides much insight in to Wheeler's lengthy career as a scientist, scholar, and teacher. The bulk of the material is from the 1950s to the 1990s and covers the wide scope of his professional endeavors, from his teaching at Princeton University and the University of Texas, to his many publications, to his consultation work with government agencies, industry, and atomic energy projects, to his numerous public talks and lectures.