A confraternity book (German: Verbrüderungsbuch, Latin: liber confraternitatum or confraternitatis), also called a liber memorialis (memorial book) or liber vitae (book of life), is a medieval register of the names of people who had entered into a state of spiritual brotherhood (confraternity) with a church or monastery in some way, often by visiting it in the capacity of a pilgrim. Persons named in such a book were actively remembered in the prayers of the priests or monks. In many cases these books were established as early as the 8th century and continued up to the 13th century. So-called Jahrtagsbücher (year books) are in many ways their successors.
Confraternity books are a rich source for prosopography and historical linguistics of the early Middle Ages.