Beware of altruism. It is based on self-deception, the root of all evil.

Love is what still goes on when you're not horny.

It would take centuries and he must grow and grow and grow, but he was in no hurry--he grokked that Eternity and the ever-beautifully-changing Now were identical.

The second best thing about space travel is that the distances involved make war very difficult, usually impractical, and almost always unnecessary. This is probably a loss for most people, since war is our race's most popular diversion, one which gives purpose and color to dull and stupid lives. But it is a great boon to the intelligent man who fights only when he must-never for sport.

I never learned from a man who agreed with me.

Once upon a time there was a Martian named Valentine Michael Smith.

There comes a time in the life of every human when he or she must decide to risk ‘his life, his fortune and his sacred honor’ on an outcome dubious. Those who fail the challenge are merely overgrown children, can never be anything else.