In 2023-2024, Trento University Engineering Library (BUM) embarked on a groundbreaking initiative: replacing its open-shelf monograph collection using the widely-adopted Dewey Decimal Classification instead of a traditional alphanumeric classification system. This ambitious undertaking, which would have normally entailed a manual reclassification of approximately 25,000 individual holdings, was successfully expedited firstly through a strategic utilization of Ex- Libris Alma’s advanced analytics capabilities and then through a huge catalogue revision work by librarians. Ex-Libris provided tailored IT support to automate the reclassification process, resulting in a highly efficient and accurate implementation of the new classification scheme.