Through the web of library catalogues, library management systems and myriad digital resources, libraries have become repositories not only for physical and digital information resources but also for enormous amounts of data about the interactions between these resources and their users. Bringing together leading practitioners and academic voices, this book considers library catalogue data as a vital research resource. Divided into four sections, each approaches library catalogues, collections and records from a different angle, from exploring methods for examining such data; to the politics of catalogues and library data; their interdisciplinary potential; and practical uses and applications of catalogues as data. Other topics the volume discusses include: * Practical routes to preparing library catalogue data for researchers * The ethics of library metadata privacy and reuse * Data-driven decision making * Data quality and collections bias * Preserving, resurrecting and restoring