The letters are chiefly addressed to John Stuart Blackie, but a great number are to his wife, and several are written by Blackie himself. They include the correspondence of Dr Archibald Stodart Walker, Blackie's nephew. The correspondence covers Blackie's wide range of interests, which included religion, philosophy, education, language, the classics, modern Greece and its poetry, German literature, the Highlanders and their language and literature, the Highland clearances, Scottish nationalism, and various topics of the day; and furnishes the opinions entertained on these subjects by those of his contemporaries who were interested in them. Anna M Stoddart's dating of some of the undated letters has been followed.