The Peale family is best known as a family of artists; however, family interests and activities were much more wide-ranging. The best known Peale is Charles Willson Peale (1741-1827, APS 1786), who produced more than one thousand paintings, including hundreds of portraits of leading Americans during the colonial and early national periods. Peale was married three times, to Rachel Brewster (1744-1790), Elizabeth de Peyster (1765-1804), and Hannah More (1755-1821). He had eighteen children, eleven of whom reached adulthood. Three of Charles Willson Peale's sons became artists: Raphaelle Peale (1774-1825), Rembrandt Peale (1778-1860), and Rubens Peale (1784-1865). A fourth son, Titian Ramsay Peale (1799-1885, APS 1833), was a naturalist (who made drawings on the exploring expeditions he accompanied) and pioneer in photography, and another son, Benjamin Franklin Peale (1795-1870), became a naturalist and paleontologist. Peale's daughter Sophonisba Angusciola was married to Coleman Sellers (1781-1834), an inventor and manufacturer of machinery, including locomotives. Two of their sons, George Escol Sellers (1808-1899) and Coleman Sellers (1827-1907, APS 1872), were inventors and engineers. The latter served as director of the construction of the hydro-electric power development at Niagara Falls. He was married to Cornelia Wells Sellers (1831-1909). One of their grandsons was Charles Coleman Sellers (1903-1980, APS 1979), a librarian and historian and the author of several studies of the Peale family, including a Charles Willson Peale biography.

An electrical engineer, inventor, and entrepreneur, Elihu Thomson was an innovator in electrification in both a technical and corporate sense. With interests that ranged from the technical (electrical meters, high-pressure steam engines, dynamos, generators) to scientific (fused quartz optics, X-rays), Thomson acquired over 700 patents in his career, and in 1882, founded one of the early electrical corporations in the United States, the Thomson-Houston Company, which merged with the Edison Electric Company in 1892 to form the General Electric Company. The Thomson Papers are a massive and nearly comprehensive collection documenting the wide range of Thomson's scientific and technical interestsm from his electrical experiments, inventions, and patents, to his interests in astronomy, geology, and medicine, as well as his role in the development of two major corporations involved in electrification, the Thomson-Houston Electric Company and General Electric Company. Roughly three quarters of the collection is dated between 1890 and 1920 when Thomson was associated with General Electric, and was active in professional groups such as the American Institute of Electrical Engineers (AIEE), International Electrotechnical Commission. His research interests. The balance of the collection is comprised of eight boxes and five volumes relating to Thomson's patents; a series of notebooks kept at Central High School; 43 letterbooks, 1882-1936; diaries of trips to Europe; notebooks on genealogy; scrapbooks of cards, photographs, clippings, and other souvenirs; and 2 vols. of tributes on his eightieth birthday, etc.

Though the Miscellaneous Manuscripts collection is composed of items that do not fall readily into any other existing collection, the two dominant intellectual areas represented in the collection are Early American History and History of Science.