Mankind which began in a cave and behind a windbreak will end in the disease-soaked ruins of a slum.

There is no upper limit to what individuals are capable of doing with their minds. There is no age limit that bars them from beginning. There is no obstacle that cannot be overcome if they persist and believe.

I do not believe I have any immortality. The greatest evil in the world today is the Christian religion

If you are in difficulties with a book, try the element of surprise: attack it at an hour when it isn't expecting it.

The true sweetness of chess, if it ever can be sweet, is to see a victory snatched, by some happy impertinence, out of the shadow of apparently irrevocable disaster.

The too perfect security of the Upper-worlders had led them to a slow movement of degeneration, a general dwindling in size, strength, and intelligence.

To ride a bicycle properly is very like a love affair-chiefly it is a matter of faith. Believe you do it, and the thing is done; doubt, and, for the life of you, you cannot.