The book is a short and relatively elementary textbook suitable for both initial and in-depth study of game theory; it conducts research on mathematical models of decision-making in conflict. For the first time in the domestic scientific literature, a systematic presentation of a unified theory of static and dynamic games is given. Finite and endless antagonistic games, multi-step games, collisionless and cooperative games, differential games are considered. Each chapter contains tasks of different complexity. The book is intended for undergraduate and graduate students of universities, economic and technical educational institutions, is of interest both for mathematicians working in the field of game theory and for specialists in economics, management theory and operations research.