Letters and papers relating to Sparks's research on Benjamin Franklin and the publication of an edition of the latter's writings. There are also extracts from Sparks's journal, 1831-1841, relating to his Franklin researches.

These selected papers include correspondence concerning Franklin, Franklin's descendants, and Franklin's papers, extracts from Philadelphia newspapers on Franklin, papers used in Sparks' biography, miscellaneous entries in his diary (1830-1854) relating to his search for Franklin manuscripts, and his preparation of an edition of Franklin's writings. Correspondents include Henry Stevens, Jr.; Henry Stevens, Sr.; Benjamin Vaughan; Petty Vaughan; James Mease; H. D. Gilpin; J. Francis Fisher; Franklin Bache; and others.

These papers reflect Isaac Hays' interests and activities in the medical profession and as an editor. His interest in paleontology, especially in the controversy with G. W. Featherstonhaugh, is also represented. There is one separate volume (77 letters) containing correspondence about natural history and naturalists, written to Hays by C. L. Bonaparte, George Ord, Thomas Say, and Charles A. Lesueur. The correspondence in the larger collection, however, contains much material on the American Journal of the Medical Sciences, particularly illuminated in the correspondence with John D. Godman. The I. Minis Hays material consists of letters from doctors, relating to medicine and medical publications and editing, as well as medical organizations. Most significant of the correspondence is that with John Shaw Billings (ca. 60 letters).