It was equally imperative that this chain of reactions should always tend to dampen, to die out. It must not build up, or the uranium mass would explode within a time interval too short to be measured by any means whatsoever. Nor would there be anyone left to measure it.

A slave cannot be freed, save he do it himself. Nor can you enslave a free man; the very most you can do is kill him!

Happiness consists in getting enough sleep. Just that, nothing more.

Budget the luxuries first.

My vocal cords lived their own life, wild and free.

He had learned that close-held secrets could often be cracked by going all the way to the top and there making himself unbearably unpleasant. He knew that such twisting of the tiger's tail was dangerous, for he understood the psychopathology of great power.

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.