This volume expands and complements the three-volume work of E. N. Fragkiskos and Chrysostomos Florentis, The Library of Patmos, A Catalogue of Documents, 15th-19th centuries, Athens: Centre for Neohellenic Research, National Hellenic Research Foundation (Athens 1993, 1995 and 1996). The fourth volume lists books that were added to the Library of the monastery of St John the Theologian until the early 1990’s. It also includes documents from periods covered by the earlier volumes that were acquired after the publication of volume 3 in 1996. The majority of these acquisitions are related to private collections that were recently transferred or donated to the Library. The volume also addresses groups of liturgical books that were collected in numerous churches, as well as the books of the female monastery Hagia ton Hagion.