Prayer is present in almost all social areas, discourses and medial formations of the Middle Ages. It bridges the border between this world and the hereafter, contributes to the medialisation of salvation and grace, and occupies a position that is as central as it is rich in prerequisites within the religious constructions of reality and order of the time. The historical scope of prayer is strikingly disproportionate to the little attention it receives within medieval research. This is where this thematic booklet comes in: it profiles prayer as an object whose cultural-historical relevance has yet to be discovered. Especially its ubiquity in medieval society argues for a profitable and only interdisciplinarily viable research programme.