Edited by Richard B. Sher, this tenth volume in the Yale Research Edition of Boswell's correspondence collects the surviving letters exchanged between James Boswell (1740-1795) and his lifelong friend, the Edinburgh banker, civic leader, and philanthropist Sir William Forbes of Pitsligo (1739-1806).

Having become close friends in Edinburgh around 1759, Forbes served for more than three decades as Boswell's most trusted Scottish advisor on financial, family, moral, and religious matters, and accompanied him on parts of his later Scottish jaunts. Following the death of Boswell's wife Margaret Montgomerie in 1789 and Boswell's own death in 1795, Forbes acted as guardian to Boswell's younger children and as one of his three literary executors alongside William Johnson Temple and Edmond Malone.

The volume contains 111 annotated letters, most published here for the first time: 79 exchanged between Boswell and Forbes between 1772 and 1794, and 32 additional letters involving other correspondents. The edition draws extensively on manuscripts in the Yale Boswell Collection and on the Fettercairn Papers (discovered at the Forbes family seat by Claude Colleer Abbott in 1930-1931) now housed in the National Library of Scotland.