The books required for the celebration of the Church's divine services are specific to each ecclesial tradition. The following books are those belonging to the Byzantine liturgical tradition that is the normal usage of the Eastern Orthodox Churches. There are some differences between the Greek and Slavic traditions within the larger Byzantine tradition, and these will be indicated below in the sections covering the relevant books. 
Note: The Eastern Orthodox Church does NOT celebrate Mass. The Mass is the Eucharistic celebration according to the Latin rite. The Eastern Orthodox Church celebrates the Eucharist according to Byzantine traditions, and thus refers to it as a Liturgy. The most commonly celebrated forms of the Divine Liturgy are the Liturgy of St. John Chrysostom, the Liturgy of St. Basil, and the Liturgy of the Presanctified Gifts, but there are others such as the Liturgy of St. James; the Liturgy of St. Mark; the Liturgy of St. Gregory the Great and the Liturgy of St. Tikhon of Moscow.
