This collection includes correspondence, notebooks, and memorandum books, lecture notes, published and miscellaneous papers, and academic and military records.

Apart from its importance for the study of Hale's personal and professional life, the collection is one of the richest sources for the history of science in the United States in the early twentieth century. It contains a good deal of significant material relating to the theoretical and instrumental development of astrophysics and the history of the Mount Wilson and Palomar Observatories. The collection is of singular importance for the study of science and government, particularly with respect to the affairs of the National Academy of Sciences and the National Research Council. It documents much of the early history of the California Institute of Technology. Finally, it contains substantial material on the general affairs of the scientific community in the United States and Europe [from Kevles 1968].

Theodore Dunham, Jr, (1897-1984) was an American astronomer, physicist, and physician. Throughout his career, Dr. Dunham pioneered research on interstellar cosmic rays, the development of telescopes, stellar spectrophotometry, the study of interstellar material and the spectrophotometry of cells. The Theodore Dunham , Jr. Papers (1921-1984) contain professional correspondence, research notes, published and unpublished works by Dunham and others, detailed photographs and oversize sketches of astronomical observations, administrative details of the Mount Desert Island Astronomical Association and of a career-long association with the Fund for Astrophysical Research. Includes some medical research, but primarily contains his astrophysical research conducted at Mount Wilson Observatory, California and Mount Stromlo Observatory, Australia.

During the mid- to late-1970s, the American Institute of Physics sponsored a project to conduct oral history interviews documenting the recent history of astrophysics, eventually accumulating over 400 hours of fully transcribed and edited audio tapes. The project organizers placed a particular emphasis on documenting the various subdisciplines of cosmology and astronomical spectroscopy. The History of Modern Astrophysics Collection is an important resource for the history of astrophysics in the latter half of the twentieth century. The collection is arranged in two series, the first consisting of transcripts of 52 interviews of 46 astrophysicists recorded between 1976 and 1979 by members of the Center for the History of Physics at the American Institute of Physics. The second series consists of 65 reels of microfilm of significant sets of correspondence for individual astrophysicists. The original oral history tape recordings are housed at AIP.