Letter listing for 1740–1749
- Frederick II, king of Prussia [the Great] to Luise Dorothea, Herzogin von Sachsen-Gotha-Altenburg [née von Sachsen-Meiningen], 1740
- Henry Brooke to Alexander Pope, 1739 / 1740
- Claude Adrien Helvétius to Gabrielle Émilie de Châtelet-Lomont d’Haraucourt, marquise Du Châtelet-Lomont [née Le Tonnelier de Breteuil], before 1741
- Alexander Pope to George Arbuthnot, 1740
- Jean Jacques Rousseau to Pierre de Chaponnay, baron de Morancé, 1740
- Adam Smith to Margaret Smith [née Douglas], c. 1740
- Swift's friends classed by their characters by Jonathan Swift, before 1740
- Jonathan Swift to [unknown], before 1740
- “Lettre sur les inconvénients attachés à la littérature” by Voltaire [François Marie Arouet], c. 1740
- Voltaire [François Marie Arouet] to [unknown], c. 1740
- Voltaire [François Marie Arouet] to Frederick II, king of Prussia [the Great], Charles Étienne Jordan and Dietrich von Keyserlingk, graf von Keyserlingk, 1740/1741
- Voltaire [François Marie Arouet] to Marie François de Paule Le Fèvre, marquis d’Ormesson, c. 1740 [translation from French into English]
- Philip Dormer Stanhope, 4th earl of Chesterfield to Philip Stanhope, January 1740
- Françoise Paule Huguet de Graffigny [née d’Issembourg Du Buisson d’Happoncourt] to François Antoine Devaux, 1 January 1740
- Voltaire [François Marie Arouet] to Henri Pitot, 2 January 1740