This paper introduces game theory, a mathematical framework for analyzing strategic interactions among rational decision-makers. It focuses on fundamental concepts such as decision theory, Nash equilibria, and cooperative games. The paper discusses how game theory can be used to model conflict and cooperation, and how it differs from price theory in its assumptions about rationality and information. The paper begins with a review of decision theory, which provides the foundation for understanding game theory. It then introduces the concept of Nash equilibrium, which is a central idea in game theory. A Nash equilibrium is a situation in which each player's strategy is the best response to the strategies of the other players. The paper explains how Nash equilibria can be found in strategic-form games and how they can be extended to more complex games with incomplete information. The paper also discusses refinements of the Nash equilibrium concept, such as sequential equilibrium, which requires that players' strategies be rational in every subgame of the game. It also introduces the concept of correlated equilibrium, which allows for the possibility of players coordinating their actions through a mediator. The paper concludes by discussing the importance of game theory in the social sciences, particularly in understanding strategic interactions among rational decision-makers. It emphasizes that game theory provides a powerful tool for analyzing economic and social phenomena, and that it has important applications in economics, political science, and other fields.This paper introduces game theory, a mathematical framework for analyzing strategic interactions among rational decision-makers. It focuses on fundamental concepts such as decision theory, Nash equilibria, and cooperative games. The paper discusses how game theory can be used to model conflict and cooperation, and how it differs from price theory in its assumptions about rationality and information. The paper begins with a review of decision theory, which provides the foundation for understanding game theory. It then introduces the concept of Nash equilibrium, which is a central idea in game theory. A Nash equilibrium is a situation in which each player's strategy is the best response to the strategies of the other players. The paper explains how Nash equilibria can be found in strategic-form games and how they can be extended to more complex games with incomplete information. The paper also discusses refinements of the Nash equilibrium concept, such as sequential equilibrium, which requires that players' strategies be rational in every subgame of the game. It also introduces the concept of correlated equilibrium, which allows for the possibility of players coordinating their actions through a mediator. The paper concludes by discussing the importance of game theory in the social sciences, particularly in understanding strategic interactions among rational decision-makers. It emphasizes that game theory provides a powerful tool for analyzing economic and social phenomena, and that it has important applications in economics, political science, and other fields.