Introduction: Unfortunately, it is a general observation that a large segment of today's Orthodox Christians is not adequately informed on issues of faith, worship, and life. They have little knowledge of these topics, sometimes not correct, and even contrary to what the Church of Christ teaches, based on the Holy Scripture and its long Tradition.

This observation is not our own. It is expressed or stated by official voices of its shepherds and ecclesiastical publications. Bishops have declared before the Holy Hierarchical Synod: "Sermons are given, both orally and in writing, but what is happening, after all, why does our people remain uninstructed? What is to blame?" (magazine "Church" 2010, p. 405).

"Our people are uninstructed, and let us ask again if this observation honors us, as well as who bears the responsibility for the ignorance of our people" ("Church" 2013, p. 171).

Without having the intention to replace, even in the slightest, our ecclesiastical leaders in their prophetic work, nor to ignore the existence of very important and lengthy books by distinguished authors that address the related topics, in this Series of brief volumes we offer to willing clergy—as help for their work—and lay readers a concise "bouquet" of texts, which are easy to read, understandable, do not cost much (in a time of crisis), and aspire to provide the necessary knowledge to every Orthodox Christian.