Financial behavior is a complex subject because how people should behave according to traditional finance often differs from how they actually behave. Although traditional and behavioral finance play important roles in understanding investor and market behavior, this book focuses on behavioral finance. Behavioral finance uses insights largely from finance, psychology, and other disciplines to explain how people act and how their behavior affects markets and other financial applications. This chapter provides an overview of behavioral finance, followed by a brief explanation of the book’s purpose, distinguishing features, and intended audience. The chapter outlines the book’s structure of: (1) financial behavior and psychology, (2) financial behavior of major players, (3) financial and investor psychology of specific players, (4) psychology of financial services, (5) behavioral aspects of investment products and markets, (6) market efficiency issues, and (7) application and future of behavioral finance.