English summary: This major work edition of the "Propst-Handbuch" (provost handbook) of Medingen produced at around 1479 represents the first complete edition of a liturgical manuscript from a North German nunnery. The documents in Latin and in the popular vernacular, which include musical notation, cover the main stages of monastic life ranging from Christmas to holy days, from oblation to funeral, and also include the Low German statutes...