Rationem reddere. Un’introduzione ragionata

The volume Rationem reddere. Law, Assistance, Technical and Scientific Culture explores the historical meanings of ratio and reddere rationem in late medieval and early modern Italy, highlighting how measurement, calculation, and order functioned as fundamental tools for governing social, economic, legal, and cultural realities. Adopting an interdisciplinary approach that brings together legal, economic, welfare, technical, and communication history, the volume examines a wide range of sources – abacus books, mercantile manuals, accounting records, normative and historiographical texts, and charitable documentation – focusing on the media of rationalization and their intended audiences. The contributions demonstrate that accounting practices, credit systems, monetary measurement, and technical writing were not merely operational instruments but also vehicles for political legitimation, social control, and moral responsibility. Special attention is given to charitable institutions, the transformation of administrative structures, the development of bureaucratic apparatuses, and the pedagogical and communicative role of mathematical and mercantile knowledge. Overall, the volume offers a coherent interpretation of the processes of rationalization that accompanied the transition from the Middle Ages to Modernity, emphasizing the decisive role of an intermediate, vernacular, and technical culture in shaping the foundations of modern economic thought and the languages of power.