Thomas Aquinas is best known as a medieval theologian. However, his interests included not only theological problems - he was also a philosopher who proposed original solutions to the main questions of being. accumulated knowledge on ontology, epistemology, ethics and theological issues. It sets out a rational system based on truths that are considered revealed by God.This publication includes a number of issues that, on the one hand, seem to be key to understanding the philosophy of Thomas Aquinas, and on the other hand, remain the most relevant for the modern reader .The text is provided with detailed comments and explanations by Konstantin Bandurovsky.The publisher's layout has been saved in a4.pdf format.