Undervaluations caused by neglect or prejudice may persist for an inconveniently long time, and the same applies to inflated prices caused by over-enthusiasm or artificial stimulants.

The individual investor should act consistently as an investor and not as a speculator. This means ... that he should be able to justify every purchase he makes and each price he pays by impersonal, objective reasoning that satisfies him that he is getting more than his money's worth for his purchase.

You must never delude yourself into thinking that you're investing when you're speculating.

Individuals who cannot master their emotions are ill-suited to profit from the investment process.

Buy not on optimism, but on arithmetic.

For 99 issues out of 100 we could say that at some price they are cheap enough to buy and at some price they would be so dear that they would be sold.

The market is a pendulum that forever swings between unsustainable optimism (which makes stocks too expensive) and unjustified pessimism (which makes them too cheap). The intelligent investor is a realist who sells to optimists and buys from pessimists.