CODICUM is a groundbreaking research project funded by the European Research Council (Synergy Grant 2024) that investigates the significance of the medieval manuscript book in shaping Northern Europe between c. 1000 and 1500. We focus on a unique collection of over 50,000 parchment book fragments found in five Nordic countries - Sweden, Finland, Denmark, Norway, and Iceland. These fragments represent a remarkable survival of what once were complete books, and offer a unique insight into everyday literary culture, lost to most of Europe. Our work seeks to understand how the texts within these books disseminated across the region, how they were used, and how they reflected the different communities and networks involved in their production and consumption. The project seeks to contribute to and re-evaluate European book history using these collections.