“Summa Theologiae” (Summa theologica), the most significant philosophical work in its influence on the Christian world. The main work of the great Christian philosopher and theologian, the greatest scholastic and metaphysician Thomas Aquinas (1225–1274). He had a huge influence on the development of Orthodox “school theology”; his influence can hardly be overestimated. The entire “Summa Theology”, an excellent anthology on a whole array of issues of Christian faith and life. In many of his arguments (“immaculate conception” of the Virgin Mary; “the unconditional primacy of the pope”, etc.), Aquinas, quite unexpectedly for a Catholic scholastic, takes an Orthodox position. The entire “Summa...” consists of three parts. The work is a series of treatises, but the basis of the division is the questions of Thomas’s opponents, then an opinion contradicting these “objections” is given, which, however, does not seem sufficiently convincing or exhaustive to Aquinas, and only then (after the word “I answer”) the solution to the problem, which belongs to to the author.