The book “Fundamentals of Orthodox Doctrine” provides a brief summary of the fundamentals of the Orthodox faith: what the Orthodox faith is; what are the sources of knowledge about it - Holy Scripture and Holy Tradition; the fundamental doctrine of the Triune God; the doctrine of the world created by God; the doctrine of man created in the image of God, and of the God-man Jesus Christ and the redemption of man accomplished by Him; teaching about the Second Coming of Christ, the end of the world and the posthumous fate of man. The books “Fundamentals of Orthodox Doctrine”, “Fundamentals of the Canonical Structure and Liturgical Life of the Orthodox Church” and “Fundamentals of Orthodox Moral Teaching” are intended for use as a teaching aid in the system of additional religious education, in the process of catechesis, as well as for educational activities in parishes and outside the church fence. The publishing layout is saved in PDF A4 format.