Game theory is the mathematical study of interaction among independent, self-interestedagents. The audience for game theory has grown dramatically in recent years, and now spansdisciplines as diverse as political science, biology, psychology, economics, linguistics, sociologyand computer science–among others. What has been missing is a relatively short introductionto the field covering the common basis that anyone with a professional interest in game theoryis likely to require. Such a text would minimize notation, ruthlessly focus on essentials, andyet not sacrifice rigor. This Synthesis Lecture aims to fill this gap by providing a concise andaccessible introduction to the field. It covers the main classes of games, their representations,and the main concepts used to analyze them.