To achieve long-term success over many financial market and economic cycles, observing a few rules is not enough. Too many things change too quickly in the investment world for that approach to succeed. It is necessary instead to understand the rationale behind the rules in order to appreciate why they work when they do and don't when they don't.

All an investor can do is follow a consistently disciplined and rigorous approach; over time the returns will come

Many LBOs are man-made disasters. When the price paid is excessive, the equity portion of an LBO is really an out-of-the-money call option. Many fiduciaries placed large amounts of the capital under their stewardship into such options in 2006 and 2007.

To a value investor, investments come in three varieties: undervalued at one price, fairly valued at another price, and overvalued at still some higher price. The goal is to buy the first, avoid the second, and sell the third.

Value investing requires a great deal of hard work, unusually strict discipline, and a long-term investment horizon. Few are willing and able to devote sufficient time and effort to become value investors, and only a fraction of those have the proper mind-set to succeed.

We don't deal in absolutes. We deal in probabilities.

Do not accept principal risk while investing short-term cash: the greedy effort to earn a few extra basis points of yield inevitably leads to the incurrence of greater risk, which increases the likelihood of losses and severe illiquidity at precisely the moment when cash is needed to cover expenses, to meet commitments, or to make compelling long-term investments.