This paper investigates different theories of the nature of a monetary economy focussing on the specific difference associated with money as the unit of value. The roles of money and of the financial circulation are considered and the specific difference associated with each is evaluated. Theoretical arguments associated with classical political economy, Marx, and Schumpeter are considered. An argument is put forward concerning the importance of money and of the financial circulation.L'article examine différentes théories concernant la nature d'une économie monétaire, en insistant sur la différence spécifique associée à la monnaie comme unité de valeur. Les rôles de la monnaie et de la circulation financière sont considérés et l'on évalue l...