Book excerpt: A smart trader needs to know what other traders are thinking and doing. Professional traders and investors use a wide range of indicators—some well-known, some not so well-known—to gauge the state of the market. Market Indicators introduces the many key indicators used by professional traders and investors every day. Having stood the test of time, these indicators will alert the trader to market situations that offer the best chance to trade profitably. Richard Sipley is a portfolio manager for Boston Private Bank and Trust Company, responsible for trading millions of dollars of assets. Sipley uses these indicators every day in his trading and investing, and he draws on that experience to explain what they are, how they work, and how to use them.