It's almost impossible to overpay the truly extraordinary CEO... but the species is rare.

The value of market esoterica to the consumer of investment advice is a different story. In my opinion, investment success will not be produced by arcane formulae, computer programs or signals flashed by the price behavior of stocks and markets. Rather an investor will succeed by coupling good business judgment with an ability to insulate his thoughts and behavior from the super-contagious emotions that swirl about the marketplace.

Anything can happen in stock markets and you ought to conduct your affairs so that if the most extraordinary events happen, that you're still around to play the next day.

The thing to do is to keep your mind when the world around you is losing theirs.

What an investor needs is the ability to correctly evaluate selected businesses. Note that word “selected”: You don't have to be an expert on every company, or even many. You only have to be able to evaluate companies within your circle of competence. The size of that circle is not very important; knowing its boundaries, however, is vital.

None of this means, however, that a business or stock is an intelligent purchase simply because it is unpopular; a contrarian approach is just as foolish as a follow-the-crowd strategy. What's required is thinking rather than polling. Unfortunately, Bertrand Russell's observation about life in general applies with unusual force in the financial world: "Most men would rather die than think. Many do."

I knew a lot about what I did when I was 20. I had read a lot, and I aspired to learn everything I could about the subject.