Includes general administrative and faculty files, records of the Agassiz Station and Boyden Stations in Peru and South Africa and of the Phillips Library. Directors' files include correspondence, letterbooks, diaries, observational data, and grant and contract files of Directors W.C. Bond (1845-1859), G.P. Bond (1859-1865), J. Winlock (1866-1875), E.C. Pickering (1876-1919), S.I. Bailey (1919-1921), H. Shapley (1921-1952), D. Menzel (1952-1966) and L. Goldberg. In some instances, the directors' files include personal and professional papers of the director (especially Pickering, Shapley and Menzel). Pickering materials include letterbooks, 1878-1919, and incoming correspondence (1875-1919) with eminent astronomers and Harvard officials, and financial records, 1903-1926. Menzel correspondence relates in part to building construction, equipment, and grant funding. Goldberg administrative records concern research projects such as Skylab, solar eclipses of 1970 and 1972, solar satellites and observatories; Smithsonian Astrophysical Observatory and other affiliated observatories; and faculty and staff. Also correspondence files of W.B. Gerrish concerning the Boyden Stations; B.J. Bok; W.J. Fisher concerning meteors; E.S. King; and F. Watson containing observation of a 1922 meteor. Agassiz Station records include correspondence, 1938-1953, of Henry A. Sawyer with observatory staff concerning observations and photographic plates.

Boyden Station materials include correspondence, 1889-1927, between Arequipa and Cambridge staff; and Bloemfontein correspondence, contracts, specifications, financial records, reports, 1924-1952, of weather conditions (monthly and hourly) at the station. Records of Phillips Library include accession books, memorandum book, 1903-1911, and stock books. General material includes accounts; records of expenditures; payrolls and other financial records; computations including those of chronometric expedition, 1849-1855; observational data; research contracts, 1947-1958, for solar observatory at Sacramento Peak, New Mexico; drawings of 1858 comet and celestial objects, 1872-1874, by E.L. Trouvelet; building blueprints; cartes photographiques du ciel; photographs of Peruvian station; finding charts of Magellanic clouds; shipment lists; astronomical and meteorological scrapbooks, 1851-1892; and journals and notebooks of S.I. Bailey. This material was generated by the research stations in Peru, South Africa, the Mandeville Station in Jamaica, and the Observatory in Cambridge. Significant records exist relating to specific astronomical phenomena such as the solar eclipse of 1932 and meteor shower of 1898; and also to scientific conferences and meetings including the International Astronomical Union meeting in 1932 in Cambridge.