A pioneer in ethnographic and linguistic studies of the American Indian and one of the most active members of the American Philosophical Society, Peter Stephen Du Ponceau helped to establish the American Philosophical Society's reputation as one of the world's foremost centers for the study of American Indians and their languages. The Peter Stephen Du Ponceau collection consists of correspondence on legal matters, Indian linguistics, silk culture, maritime law, the American Philosophical Society, and various publications of the early nineteenth century. The collection also includes several essays by Du Ponceau, most of which deal with maritime law.

The Anthony F. C. Wallace Papers include correspondence to and from 20th century anthropologists, ethnologists, historians, linguists, and psychiatrists and provides a wealth of resources for the study of technological and social change, American Indians, culture and personality, revitalization movements, the anthropological study of religion, and the cultural and biological bases of behavior. In addition to Wallace's correspondence, research notes, and drafts, the collection includes Wallace family correspondence and photographs, as well as Wallace's writings from childhood through recent years.