A major, but largely neglected source of evidence for understanding Orthodox monasticism in the Crusader East is the body of writing produced in the monasteries themselves. Over a hundred manuscripts from the major monasteries survive, containing as well as original compositions, many copies of early devotional, hagiographical and liturgical works. The reasons for copying certain works and the uses made of them, and the nature of the original compositions – hagiographical, theological, liturgical and polemical –are the focus of this chapter.