The Library of Saint John's Monastery in Patmos, is considered as one of the most important historic librarieds of the Christianity. In the 13th century it consisted almost entirely of theological codes. The library has a variety of books (1.000 pieces), scrolls (1.000 pieces), archives (13.000 pieces) and codes, dating from the begining of printing! The most important books are the manuscripts of Osios Christodoulos.

It has 330 codes in total (267 in vellour and 63 in cotton) from which 109 are administrative, 107 are "moral", 31 are linked to Saint John (theological) and the rest concern a variety of topics. One is classical referring to the "Accusation of Aristotelis" (Aristotle).

The list of books housed in the library in 1355 shows the wide spirit that prevailed in the Monastery. In the 14th century monks red a variety of books including the Greek Philosophers such as Xenophon and Plato.

The library kept its religeous content throughout the the years.

The library's historic building is found in the monastery and is impressive. It has a central hall with rooms all around it, accommodating all the archives and biographic material. There are stone pillars supporting the roughcast arches, following the characteristic architecture of the monastery. Bookcases cover almost all walls, hosting manuscripts and books.

For Saint John's Monastery (Agios Ioannis), see separate listing