In the first part of the Treatise , Keynes develops an approach qualified as institutionalist to study the nature of money. This approach has inspired an important body of contemporary heterodox work on money as economic institution (Aglietta et Cartelier, 1999; Smithin, 2000). We wish to point out that a sociohistorical theory of money as an institution can find in the Treatise certain fundamental concepts. The Treatise contains material essential to the reconstruction of a sociology of money based on a theory of money as a unit of account and means of payment and for an analysis of the social mode of production of bank money as an economic institution typical of modernity.