In this volume are published a series of ecclesiological articles and studies by Metropolitan Ioannis Zizioulas of Pergamum, most of which were originally published in English, French and German. The undertaking of this project by "Domos" publications has its own little history; it started almost twenty years ago and Nikos Kourabis, Kaiti Chiotelli and Nikos Asproulis contributed in particular to it, as well as a group of young theologians at the time, the Who, being in one way or another immersed in the work of Ioannis Zizioulas, also took on the arduous task of translating his ecclesiological studies. The present edition, which was edited by Stavros Yiagazoglou, aspires to be a basis and starting point for study, study and dialogue of theological thought both with the burning ecclesiological problems and with the modern man who is confronted with the fundamental existential questions.