SUMMARYThis article transcripts and comments a hitherto unpublished letter from Dugald Stewart to Thomas Robert Malthus. In April 1820, Malthus published the first edition of his Principles of Political Economy and sent a copy to Stewart, who had turned away from political economy a few years previously. Our comment considers the seminal role that Stewart's teaching and writings played in the development of political economy at the beginning of the nineteenth century. It then sheds light on the reasons advanced by (...) Stewart in his letter to Malthus to explain his turning away from political economy after 1814. We conclude that in 1820, Stewart may have felt somewhat overwhelmed in the operation of transmuting principles of political economy to new problems, and left this task to David Ricardo and Malthus, to whom he paid a tribute. (shrink)