The third Duke of Buccleuch (1746-1812) presided over the management of one of Britain's largest landed estates during a period of profound social, political and economic change. Tutored by Adam Smith, the Duke was also a leading patron of the Scottish Enlightenment, and his alliance with Henry Dundas dominated Scottish politics for almost forty years. Combining the approaches of intellectual, economic and agrarian history, this is the first critical study of the life and career of the Duke, focusing in particular on his relationship with Adam Smith and the improvement of his vast Scottish estates.