The present volume presents eight contributions originating from the international workshop ‘Liturgical Books and Music Manuscripts with Polyphonic Settings of the Mass in Medieval Europe’. The workshop took place in Hamburg on 3–4 November 2017, with participants from England, Italy, and Germany. The contributions focus on polyphonic settings of the Mass from the eleventh to the fifteenth century, as well as on the different types of manuscripts in which the respective settings are transmitted. The aim is to gain new insights into polyphonic singing of the Mass and the function of the manuscripts in which these polyphonic settings appear.