Games are characterized by a number of players or decision makers who interact, possibly threaten each other and form coalitions, take actions under uncertain conditions, and finally receive some benefit or reward or possibly some punishment or monetary loss. In this text, the author presents various mathematical models of games and study the phenomena that arise. In some cases, the author will be able to suggest what courses of action should be taken by the players. In others, the author hopes simply to be able to understand what is happening in order to make better predictions about the future.