This rich collection of letters and documents, which was assembled by Sol Feinstone (1888-1980) over a period of fifty years, includes material on almost all notable Americans from before the Revolution to the 1850's, as well as prominent Europeans, and there are documents relating to military affairs. There are substantial groups of letters from: John Adams, Henry Dearborn, Alexander Hamilton, Jedediah Huntington, Thomas Jefferson, Lafayette, George Washington, and a long run of letters from a Massachusetts military surgeon named Samuel Adams. Many letters, though written by Revolutionary figures, relate to events that occurred before or after the War.

Anthropologist and ethnographer Frank Gouldsmith Speck was one of Franz Boas' early graduate students and from 1907 till his death in 1950 spent his career in a variety of positions at the University of Pennsylvania, including its Museum of Archaeology and Anthropology. Unlike most of his contemporaries, Speck chose to study the cultures of Indigenous peoples of eastern North America, especially the Haudenosaunee, Cherokee, and peoples speaking Algonquian languages, such as Anishinaabe, Wabanaki, Innu, Lenape, and other Algonquian peoples within the eastern United States. Speck spent a larger amounnt of time in the field than was typical of most ethnographers, collecting documentary information and physical objects. The Frank G. Speck Papers consist of 15.5 linear feet of Speck's professional correspondence, field notes, lecture notes, and manuscripts of published and unpublished works. The material focuses on the Eastern Woodlands Indians, particularly the Catawba, Cherokee, Creek, Delaware, Houma, Haudenosaunee ("Iroquois"), Labrador Inuit ("Eskimo"), Innu ("Montagnais-Naskapi"), Nanticoke, Penobscot, Powhatan, Algonquian, and Yuchi. The collection is divided into two subcollections: Subcollection 1 is comprised of Speck's research material and correspondence, and Subcollection 2 consists of his manuscripts and related correspondence. The two subcollections were acquired separately by the Society, and were originally cataloged as the Frank G. Speck Papers (572.97 Sp3) and the Frank G. Speck Manuscripts on Native Americans (970.3 Sp3p) respectively.