Theory of knowledge (epistemology, epistemology) is a section of philosophy presented in the book in a popular, brief presentation. Theory of knowledge is a discipline that studies the nature of knowledge, its possibilities and limitations, methods of knowledge, the relationship of knowledge to reality, questions about the essence of reality, about the possible limits of the cognizability of the world, about truth and its criteria, etc. The book examines three stages in the development of the theory of knowledge - classical, non-classical, and beginning, post-non-classical.