It is a fact worth pondering that four centuries ago the evil of "an abundance or surplus" arose from its being kept off the market, while today the … - Benjamin Graham

Why could the typical investor expect any better success in trying to buy at low levels and sell at high levels than in trying to forecast what the market is going to do? Because if he does the former he acts only after the market has moved down into buying levels or up into selling levels. His role is not that of a prophet but of a businessman seizing clearly evident investment opportunities. He is not trying to be smarter than his fellow investors but simply trying to be less irrational than the mass of speculators who insist on buying after the market advances and selling after it goes down. If the market persists in behaving foolishly, all he seems to need is ordinary common sense in order to exploit its foolishness.

Though business conditions may change, corporations and securities may change, and financial institutions and regulations may change, human nature remains the same. Thus the important and difficult part of sound investment, which hinges upon the investor's own temperament and attitude, is not much affected by the passing years.

Investment is most intelligent when it is most businesslike.