Technical indicators are tools of the trade that market technicians use to determine the trends in the market. It is necessary to know the important technical indicators before one begins trading. There are many technical indicators developed in the last two centuries. Inside the trading black box are the technical indicators that professional traders use as trading tools. Technical indicators are generally categorized into two major lagging indicators and leading indicators. Some of the lagging technical indicators examined This chapter reviews these techniques to prepare the foundation for the trader to select the trading tool of his choice to begin building a technical trading system in an intelligent manner.