An old Wall Street adage states that two factors move the market: fear and greed. Although true, this characterization is far too simplistic. The human mind is so sophisticated and human emotions are so complex that the emotions of fear and greed do not adequately describe the psychology that affects people as they make investment decisions. This book is one of the first texts to delve into this fascinating and important subject. Few other texts provide this information because traditional finance has focused on developing the tools that investors use to optimize expected return and risk. This endeavor has been fruitful, yielding tools such as asset pricing models, portfolio theories, and option pricing. Although investors should use these tools in their investment decision making, they typically do not. This is because psychology affects our decisions more than financial theory does. Unfortunately, psychological biases inhibit one's ability to make good investment decisions. By learning about your psychological biases, you can overcome them and increase your wealth. You will notice that most of the chapters in this book are structured similarly. A psychological bias is first described and illustrated with everyday behavior (like driving a car). The effect of the bias on investment decisions is then explained. Last, academic studies are used to show that investors do indeed exhibit the problem. What we know about investor psychology is increasing rapidly. This second edition of The Psychology of Investing is expanded by 20 percent, with new evidence and ideas added to every chapter. Also, Chapter 8 has been rewritten to focus more on the role of human interaction in the investment process. Finally, an entirely new chapter has been included on the influence of feelings and mood on financial decision making. This material does not replace the investment texts of traditional finance. Understanding psychological biases complements the traditional finance tools. Indeed, after reading this book, you should be convinced that traditional tools are valuable.