The present work is an exposition of the Thomistic synthesis, an exposition devoted to the principles often formulated by the saint himself. We do not undertake to prove historically that all the doctrinal points in question are found explicitly in the works of St. Thomas himself, but we will indicate the chief references to his works. And our main task will be to set in relief the certitude and universality of the principles which underlie the structure and coherence of Thomistic doctrine.First, then, we will note the chief works that expound this Thomistic synthesis, and likewise point out the most faithful and most penetrating among the saint's commentators. There will follow a philosophic introduction, to underline that metaphysical synthesis which is presupposed by Thomistic theology. Then we will emphasize the essential points in this doctrine by noting their force in the three treatises, De Deo uno, De Verbo incarnato, De gratia. Finally we will note briefly their importance in the other parts of theology.