The essay focuses on the reuse of documentary fragments in the bindings of codices and printed books kept in the libraries of Trentino. The initial part of the essay introduces the background information on the general and special catalogues which were the main source for the identification of documentary fragments. This is followed by the analysis of some fragments reused in medieval codices preserved in the Public Library of Trento and in incunabula and sixteenth-century books in the San Bernardino Library Foundation of Trento. The aim of the essay is to suggest research hypotheses by examining reuse techniques in order to understand, firstly, to gather elements to identify the context that led to the reuse of documentary material and second, to study the issues related to the provenance and circulation of books, starting from the data offered by those documents.