Abstract
This article discusses the development of the Library collections concept at the University of Sheffield. It draws together several wider themes of collection management and seeks to conceive of library content as serving differing functions through different but related collection approaches. To do so effectively, it argues, it is necessary to compartmentalize collections accordingly. The idea of the facilitated collection is developed towards an operational collection whose chief focus is content supply. Alongside this, it shows how collective initiatives allow for the development of explicitly conservational collections. This improved understanding of core functions allows a research library to then think about how it presents the unique and distinctive content as an inside‑out collection. By grounding this work in the collection development plan at Sheffield, it is hoped that its specific application will be demonstrated.