Letter listing for 1740–1749
- Gabrielle Émilie de Châtelet-Lomont d’Haraucourt, marquise Du Châtelet-Lomont [née Le Tonnelier de Breteuil] to [unknown], 5 January 1740
- Alexander Pope to Edward Harley, 2nd earl of Oxford, 5 January 1740
- Voltaire [François Marie Arouet] to Claude Adrien Helvétius, 5 January 1740
- Voltaire [François Marie Arouet] to Claude Adrien Helvétius, 5 January 1740
- Voltaire [François Marie Arouet] to Jeanne Françoise Quinault [née Quinault], 5 January 1740
- Frederick II, king of Prussia [the Great] to Voltaire [François Marie Arouet], 6 January 1740
- Voltaire [François Marie Arouet] to Jean Baptiste François Durey de Mesnières, 6 January 1740
- Alexander Pope to Martha Blount [née Blount], 7 January 1740
- Voltaire [François Marie Arouet] to René Louis de Voyer de Paulmy, 2nd marquis d’Argenson, 8 January 1740
- Lodovico Antonio Muratori to Ridolfino Venuti, abate Venuti, 9 January 1740
- Voltaire [François Marie Arouet] to père Bonaventure Moussinot, abbé Moussinot, 9 January 1740
- Voltaire [François Marie Arouet] to père Pierre Robert Le Cornier de Cideville, abbé Cideville, 9–12 January 1740
- Frederick II, king of Prussia [the Great] to Voltaire [François Marie Arouet], 10 January 1740
- Gabrielle Émilie de Châtelet-Lomont d’Haraucourt, marquise Du Châtelet-Lomont [née Le Tonnelier de Breteuil] to Johann Bernoulli, 11 January 1740
- Jonathan Swift to Martha Whiteway [née Swift], 11 January 1740