The canonical collections dating from Late Antiquity to the Early Middle Ages preserved in the Capitular Library of Verona—whose written production is documented from the 6th century onward—offer valuable evidence of the process of formation of canon law in its most fluid phase. In this transitional period, between the patristic phase of the ius antiquum and the Carolingian reform, the law was born and transmitted through the materiality of books: the copying, correction, and reorganization of canons responded to the disciplinary and pastoral needs of ecclesiastical institutions. Through codicological and textual analysis of these manuscripts, this paper aims to demonstrate how the book form of the canon played a decisive role in the construction of clerical and penitential discipline. The intervention of several Veronese readers and revisers, particularly Archdeacon Pacifico and his entourage, reflects the desire to restore authority and certainty to texts compromised by errors or variants, in line with the demands for educational and normative reform promoted in the Carolingian context. The Chapter Library, closely linked to the life of the chapter, was not simply a repository of manuscripts, but a place of work and normative mediation. Book production appears as a space of mediation between written rules and disciplinary practice, between authority and community: a laboratory in which the rule becomes a book and the book, in turn, generates law.