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).

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.

Primary source materials for the history of quantum physics in the twentieth century, collected under the auspices of the American Philosophical Society and the American Physical Society, with a grant from the National Science Foundation.