The naturalist Spencer Fullerton Baird worked as Assistant Secretary and Secretary of the Smithsonian Institution from 1850 until his death in 1887. A prolific collector and writer, Baird made important contributions to American ornithology, mammalogy, and herpetology, completing three monumental works, The Mammals of North America (Philadelphia, 1859), Birds of North America (Philadelphia, 1860), written with John Cassin, and History of North American Birds (Boston, 1874-1884), 5 vols., with Brewer and Robert Ridgway. The Baird Collection includes twelve letters written by Baird to the Boston printing firm, Welch, Bigelow and Co., all regarding editorial details in printing of the History of North American Birds.

Winfrid Alden Stearns (1852-1909) was an amateur naturalist, ornithologist, and ethnologist who corresponded with several prominent experts in the natural sciences. Among his works were a collaboration with surgeon and naturalist Elliot Coues, New England Bird Life (1881-1883) and the self-published A Manual of Ornithology (1895) that was heavily criticized by university-trained naturalists. The collection consists of original letters with details about Stearns' publications, specimen donations, and ornithological work from 1871 to 1906. There are letters concerning his editorial collaboration with Coues and others, Stearn's works, and Stearns' travels to Newfoundland. Of particular interest are two letters from Charles Bendire accusing Stearns of inaccurate classification of specimens and poor proofreading of his manuscripts. (Both Stearns and Bendire worked with Coues.) The collection contains a picture of the museum Stearns curated in the 1880's.

These are to Darlington from Spencer F. Baird, Robert Carr, Edward D. Ingraham, Moses Marshall, George Ord, John Jay Smith, and John F. Watson, among others. A letter from Joseph Johnson encloses a sketch of the life of Stephen Elliott (1771-1830).

This collection consists of correspondence to Bonaparte from American scientists regarding ornithology, zoology, and specimens.

These letters discuss the fossils of southern California, as well as Indian artifacts, skulls, languages, ethnography, religion, etc. Most correspondents are represented by only one letter.

This collection of Morton letters forms part of a bound volume of incoming correspondence. It is a companion volume to the original letters in the Morton collection at the American Philosophical Society, which were also originally bound. Most of the subjects of the two collections overlap, but additional subjects in the microfilmed collection include American Indians, archaeology, Egyptology, and phrenology.

This is a small but diverse collection documenting Wheatley's interests in mines and mining technology, paleontology, mineralogy, and shells. There are sketches of Wheatley's mine near Phoenixville, Pennsylvania; estimates of costs of machinery, and a list of furnace products sent to the Centennial Exposition.

This correspondence concerning the survey of western lands was received by the United States Geographical and Geological Survey of the Rocky Mountain Region. Also includes a selection of letters sent by the Survey (1876-1878).

Material collected by Muriel Rukeyser in the late 1940s and 1950s for a proposed biography of Franz Boas, including original manuscript materials of Boas, correspondence between Boas and Rukeyser, biographical data, early family letters and documents relating to him, school and military records, family reminiscences of Boas, and some professional correspondence. There is also material specifically related to the publication of Rukeyser's biography, including notes, a synopsis of the book, and correspondence with publishers and funding agencies. There are also some of Boas' and others' publications.

This collection contains professional and personal correspondece, as well as some personal business accounts. The topics mentioned range from general ornithology to specific birds, particularly of the West Indies and South America; bird illustrations and various publications; paleontology, and zoology.

The collection is a miscellaneous group of letters of mainly British scientists and physicians, purchased as an existing autograph collection. There are a few American signatures. The letters are primarily from the nineteenth century and focus on medical and geological topics, but also there are some earlier and later dates. In addition to the letters are anatomical drawings of surgery, sketches of bones, and one geological notebook.

This is primarily a collection of letters, with some additional documents, concerning Young's interest in botany, geology, mineralogy, and natural history. There is information about Bowdoin College, where he studied under Parker Cleaveland. There is also much on the natural history of Maine, where he was the State Botanist in 1847-1849, and also on the Bangor Natural History Society. There are materials on Brazil in relation to Young's service there as the U.S. consul to Rio Grande do Sul from 1863 to 1873. There are also letters from his brother, John C. Young, and his sister, Sarah Augusta Young.

Through his craniometic studies of human races, the Philadelphia physician Samuel George Morton (1799-1851) exerted a profound influence on the development of physical anthropology in antebellum America, and made substantial contributions to mineralogy, paleontology, and natural history. Relating primarily to Morton's scientific interests, the Morton Papers include insights into Morton's perspectives on education, medical practice, geology and mineralogy, craniology, paleontology, the Wilkes Exploring Expedition (also known as the United States Exploring Expedition 1838-1842), and his two major monographs, the Crania Americana and Crania Aegyptiaca. Several of the letters were written by Morton in his capacity as corresponding secretary of the Academy of Natural Sciences of Philadelphia. Also included in this collection are Morton's "Some Remarks on the Infrequency of Mixed Offspring Between the European and Australian Races" (1850), Joseph Barclay Pentland's notes on the aborigines of Peru (ca. 1840?), and newspaper clippings on Morton's death; a diary of Morton's trip to the West Indies, 1834, a set of craniological sketches for use in Crania Americana, and a microfilm of letters in private hands, written to Morton, 1838-1844