Marginality assumes a variety of forms in current discussions of the Middle Ages. Modern scholars have considered a seemingly innumerable list of people to have been marginalized in the European Middle Ages: the poor, criminals, unorthodox religious, the disabled, the mentally ill, women, so-called infidels, and the list goes on. If so many inhabitants of medieval Europe can be qualified as marginal, it is important to interrogate where the margins lay and what it means that the majority of people occupied them. In addition, we scholars need to reexamine our use of a term that seems to have such broad applicability to ensure that we avoid imposing marginality on groups in the Middle Ages that the era itself may not have considered as such. In the medieval era, when belonging to a community was vitally important, people who lived on the margins of society could be particularly vulnerable. And yet, as scholars have shown, we ought not forget that this heightened vulnerability sometimes prompted so-called marginals to form their own communities, as a way of redefining the center and placing themselves within it. The present volume explores the concept of marginality, to whom the moniker has been applied, to whom it might usefully be applied, and how we might more meaningfully define marginality based on historical sources rather than modern assumptions. Although the volume’s geographic focus is Europe, the chapters look further afield to North Africa, the Sahara, and the Levant acknowledging that at no time, and certainly not in the Middle Ages, was Europe cut off from other parts of the globe.