Among the thousands of manuscripts that have been produced during the Middle Ages, liturgical books represent a huge percentage. Despite their great number and spread, we have a partial and imperfect knowledge of their use and function in ceremonies and services. Which types of liturgical books were produced? Who produced them, how and why? Who was their recipient? The purpose of this website is to allow historians to gain a deeper knowledge of liturgical witnesses in order to correctly place them in their context. In this respect, only the study of the primary sources offers a necessary instrument to understand medieval liturgy as an important mean for spiritual needs and an essential part of the social structure.