This contribution aims first at analyzing the very ambitious project of a new economic encyclopedia which the Abbé Morellet (1727–1819) developed in his Prospectus d’un nouveau dictionnaire de commerce. En cinq volumes in-folio proposés par souscription (Paris, Frères Estienne, 1769) which was intended to replace The Dictionnaire Universel de Commerce (1723, last edition 1768) by Savary Des Bruslons, the reference work in the economic field until the late 1760s not only in France, but in large parts of Europe at the time. For different reasons – personal, financial, conceptual and historical – Morellet’s project of a new economic encyclopedia was not realized as such – and represented a ‘failure’, at least for its author and in the eyes of the public and especially the subscribers who felt mislead by Morellet and his promising project. Nevertheless, Morellet’s project had a surprising and influential afterlife: it formed 20 years later the basis of the Dictionnaire Universel de la géographie commerçante (1799–188, 5 vols.) edited by Jacques Peuchet, a former collaborator of the Abbé Morellet and contributor to the Encyclopédie Méthodique who adapted, reconceived and transformed the original project into a new and in some ways groundbreaking economic encyclopedia.