An investor without a well thought out investment philosophy might as well be throwing their money away, because there is no use in implementing a portfolio strategy without first understanding the investment philosophy. An investment philosophy is simply a set of principles that will guide the investor's actions while making portfolio decisions. It may seem like a minor distinction, but an investment philosophy must be determined before a portfolio strategy can be implemented. Philosophy leads to an investment strategy which leads to portfolio construction, which is all worthless if investors do not have a process in place that allows them to follow these steps. Without an understanding of investment philosophy, investors will surely jump ship at the first sign of trouble in the markets or their portfolio. An investment philosophy will get its true test during a market correction or crash. The chapter presents successful investment philosophies and how they are tested during difficult markets.