From 1759 to 1762, François Quesnay had systematically appealed to an obscure physiocrat, Charles Richard de Butré, when he had to make a numerical estimate or to do a nonelementary
computation. In the present article, we use two important unpublished writings by Butré to discuss and assess the extent of his contribution to physiocratic theory. In these two works written at the end of 1766 and the beginning of 1767, Butré set himself to the task of deepening Quesnay’s political economy. Although he was, besides Quesnay, the only physiocrat who mastered the Tableau économique, he chose to develop his own analytical devices. In order to provide a more satisfactory presentation of the doctrine of the exclusive productivity of agriculture, Butré modified significantly the social classification adopted by Quesnay and all the other physiocrats. Finally, he imagined and drafted a theoretical system of public accounting that would measure and account for all kinds of economic activities, including those Quesnay had left out in his Tableau économique, such as external trade. We argue that the study of his work offers us an ideal vantage point to broaden our understanding of the nature and the history of Quesnay’s political economy.