The Typikon is the system that ‘directs’ the liturgical practice of the Eastern Orthodox churches and monasteries. The term is employed for the different systems that exist, as well as for the liturgical book in which the system is laid down. In the earliest phase of monasticism in Palestine, the words typos and canon were used (see Cyril of Scythopolis Bioi of Euthymius, Sabbas…) and later also canonarion and synaxarion (see Dimitrievski I and III). Since the Typikon directs the readings of the daily services during the year, this system and Typikon codices are important tools for the study of the composition and reading structures of the different codex types. See Portal Ω.