"We will not remove the age-old landmarks which our fathers have set (Proverbs 22:28), but we keep the tradition we have received. For if we begin to erode the foundations of the Church even a little, in no time at all the whole edifice will fall to the ground." - St. John of Damascus Perhaps our age's most definitive characteristic is a blurring of boundaries until their unitive function and meaning are lost. Often, ironically in the name of unity, protective walls are intentionally removed so that communities are "flooded" and age-old identities made fluid. Yet, have such contemporary phenomena on the social or personal plane sprung up "ex nihilo," or are they rather the fruit of centuries of incremental destruction of the age-old boundaries erected by our Fathers, first on the ecclesiological plane? In his book On Common Prayer with the Heterodox Protopresbyter Anastasios Gotsopoulos masterfully presents the wisdom of the Church's salvific delineation of the boundaries. Profoundly patristic, On Common Prayer completely puts to rest any misunderstanding or excuse as to how one must faithfully live within the boundaries while serving the salvation of all. Every angle of the matter is addressed: terms are defined, heresies identified, the consensus patrum illustrated, canons set forth. We are given the principles by which to faithfully interpret the canonical tradition, those sacred boundaries divinely established for the salvation of the world. Protopresbyter Anastasios Gotsopoulos is the rector of the Holy Church of Saint Nicholas, Patra, Greece. He is also the author of The Church of Rome and Its Bishop in the Minutes and Decisions of the Ecumenical Councils , as well as numerous articles and canonical studies.