Browse Subjects - O
- Obituaries
- Deceased Fellows and Memoirs, Australian Academy of Science, Editors: R. W. Home, L. Robin
- Observation
- The Planet Mars: A History of Observation and Discovery, William Sheehan
- Oceanography
- Bibliography on the History of the Scripps Institution of Oceanography
- Cumulated Biblography of Biographies of Ocean Scientists, Deborah Day
- Cumulative Bibliography on the History of Oceanography, 1987-2001 (1987 - ), Jacqueline Carpine-Lancre, Deborah Day
- Earth Sciences History: Journal of the History of the Earth Sciences Society (1982 - )
- A Handlist of Source Books on the History of Oceanography, Eric L. Mills
- History of Oceanography & Earth Sciences: UC San Diego Libraries, Scripps Institution of Oceanography Library
- History of Oceanography Newsletter Archive, Professor Eric Mills, Editor
- History of Oceanography: NOAA Photo Library
- Library: Marine Biological Laboratory & Woods Hole Oceanographic Institution
- Office of Coast Survey: NOAA Heritage
- Scripps Institution of Oceanography Archives
- Woods Hole Oceanographic Institution: History (2007 - )
- Optics
- Museum of optical instruments (2000 - ), Timo Mappes
- Rittenhouse: Journal of the American Scientific Instrument Enterprise (1986 - )
- Oral history
- British Library Oral History of Science Blog (2010 - )
- British Library: Oral History of British Science
- Ornithology
- Five Centuries of Veterinary Medicine: A Short-Title Catalog of the Washington State University Veterinary History Collection (1997 - ), J. Fred and Ann Smithcors
- Oxford University
- Museum of the History of Science