Even with a margin of safety in the investor's favor, an individual security may work out badly. For the margin guarantees only that he has a better chance for profit than for loss - not that loss is impossible. But as the number of such commitments is increased the more certain does it become that the aggregate of the profits will exceed the aggregate of the losses.

The defensive (or passive) investor will place chief emphasis on the avoidance of serious mistakes or losses. His second aim will be freedom from effort, annoyance, and the need for making frequent decisions.

The intelligent investor shouldn't ignore Mr. Market entirely. Instead, you should do business with him- but only to the extent that it serves your interests.

The investor should be aware that even though safety of its principal and interest may be unquestioned, a long term bond could vary widely in market price in response to changes in interest rates.

Mathematics is ordinarily considered as producing precise and dependable results; but in the stock market the more elaborate and abstruse the mathematics the more uncertain and speculative are the conclusions we draw there from. Whenever calculus is brought in, or higher algebra, you could take it as a warning that the operator was trying to substitute theory for experience, and usually also to give to speculation the deceptive guise of investment.

High valuations entail high risks.

Successful investing professionals are disciplined and consistent and they think a great deal about what they do and how they do it.