Valuing a business is part art and part science.

First, many in Wall Street - a community in which quality control is not prized - will sell investors anything they will buy.

In an inflationary world, a toll bridge (like company) would be a great thing to own because you've laid out the capital costs. You built it in old dollars and you don't have to keep replacing it.

An argument is made that there are just too many question marks about the near future; wouldn't it be better to wait until things clear up a bit? You know the prose: "Maintain buying reserves until current uncertainties are resolved," etc. Before reaching for that crutch, face up to two unpleasant facts: The future is never clear and you pay a very high price for a cheery consensus. Uncertainty actually is the friend of the buyer of long-term values.

For some reason, people take their cues from price action rather than from values. What doesn't work is when you start doing things that you don't understand or because they worked last week for somebody else. The dumbest reason in the world to buy a stock is because it's going up.

I believe the chance of any event causing Berkshire to experience financial problems is essentially zero. We will always be prepared for the thousand-year flood; in fact, if it occurswe will be selling life jackets to the unprepared.

There are three important principles to Graham's approach. [The first is to look at stocks as fractional shares of a business, which] gives you an entirely different view than most people who are in the market. [The second principle is the margin-of-safety concept, which] gives you the competitive advantage. [The third is having a true investor's attitude toward the stock market, which] if you have that attitude, you start out ahead of 99 percent of all the people who are operating in the stock market - it's an enormous advantage.