Containing over 4 linear feet of letters and documents, the Franklin-Bache Papers comprises the second largest collection of letters and documents relating to Benjamin Franklin in the APS Library. Although the scope of the collection is broad, including materials from the time of Franklin's arrival in Philadelphia to his death, the heart of the collection documents the period of Franklin's ministry in France (1776-1785) and his diplomatic efforts to win financial and military support for the revolutionary cause, as well as less intensive coverage of his ministry in England before the Revolution. Franklin's correspondence with American and French officials, financiers (personal and otherwise), and savants provides tantalizing details on the social context of Franklin's ministry in France, his intellectual life, and his growing celebrity. Much of the correspondence documents the efforts to convince French officials early in the war to support the American cause, but there is valuable material relating to the peace negotiations as well. The collection is equally rich in personal correspondence, including a rich set of letters from Mary Stevenson Hewson, Georgiana Shipley, Catherine Ray Greene, Jane Mecom, Deborah Franklin, and a number of Franklin's other relatives. The collection is arranged chronologically.

The only son of Benjamin Franklin, William Franklin served as Royal Governor of New Jersey during the critical years between 1762 and 1776. An ardent Loyalist, William split with his father over their political differences in the early days of the Revolution, and after enduring two years of imprisonment, became a leader in the Loyalist cause. He settled in London in 1782, where he worked as an agent for Loyalist claims. The William Franklin Papers are a miscellaneous assemblage of letters and documents, dealing largely with Franklin's years as Royal Governor of New Jersey. The majority of the letters are perfunctory, however they provide some information on Franklin's land holdings in New Jersey and the Ohio country. The collection includes two letters relating to Franklin's imprisonment in Connecticut during the Revolution, two affectionate letters to his sister Sarah, and one to his son William Temple Franklin.

The Welsh non-conformist minister Richard Price (1723-1791) was a moral philosopher and political and economic theorist whose ideas leant support to the American cause during the Revolution. Of broad and liberal mind, he was an integral member of the intellectual coterie surrounding William Petty, the Earl of Shelburne, and was a founding member of the Unitarian Church. Befitting a latitudinarian thinker, the range of Richard Price's correspondence is extremely broad, touching upon his rationalistic philosophy and dissenting theology, his political views on British politics, America and the American Revolution, the Constitutional settlement, the future of the United States, social reform, demography, prisons, and slavery. The ninety letters in the collection are arranged chronologically, with correspondents including Charles Chauncy (8 letters, 1772-1779), Benjamin Franklin (7 letters, 1775-1789), John Howard (11 letters and a biographical manuscript, 1770-1789), Thomas Jefferson (3 letters, 1785-1789), Benjamin Rush (8 letters, 1786-1790), and Edward Wigglesworth (3 letters, 1775-1786), as well as lesser known figures such as the reformer John Howard.

Letters (including some transcripts and photostats) from and to Vaughan from many American and British correspondents, including: Also personal correspondence and business papers of Benjamin, Charles, Petty, Samuel Sr., Samuel Jr., William, William Oliver, and Sarah Vaughan (2 boxes); lectures, mostly in shorthand (3 vols.); a large number of notes and memoranda on a wide variety of topics, such as agriculture, architecture, astronomy, diplomacy, diseases, dueling, electricity, hieroglyphs, internal improvements, medicine, meteorology, land, manufactures, politics, punctuation, religion, silk-manufacturing, stock-breeding, taxation, Unitarianism, Benjamin Franklin, John Locke, Napoleon I, Joseph Priestley, Bowdoin College, town of Hallowell, Maine; notes on the peace negotiations, 1782-1783; miscellaneous legal papers; genealogy of the Abbott-Vaughan families. For a personal account of the collection, see Mrs. Mary Vaughan Marvin, "The Benjamin Vaughan Papers," APS Proceedings 95 (1951): 246-249.

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.