This volume challenges the persistent association of the Middle Ages with closure and fixity. Bringing together a range of disciplines and perspectives, it identifies and uncovers forms of openness which are often obscured by modern assumptions, and demonstrates how they coexist with, or even depend upon, enclosure and containment in paradoxical and unexpected ways. Explored through notions such as porosity, vulnerability, exposure, unfinishedness, and inclusivity, openness turns out to permeate medieval culture, unsettling boundaries, binaries, and clear-cut distinctions.