This edition aims to offer a more comprehensive information and teaching to the reader who wishes to learn something important about the theological and practical aspects of this subject, which constitutes the essence of our ecclesiastical existence. And to contribute to the return of all of us to our true ecclesiastical roots, to emphasize the need for experiencing the salvific dimensions of the mystery, to combat the alienating distance of the lay brothers from it, as well as the transformation of the Divine Liturgy into an opportunity for recyclable individual devout expression, without the dimension of Community, Synaxis, and Church.