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.

The most important lesson in the writing trade is that any manuscript is improved if you cut away the fat.

Pessimist by policy, optimist by temperament- it is possible to be both. How? By never taking an unnecessary chance and by minimizing the risks you can't avoid. This permits you to play out the game untroubled by the certainty of the outcome.

What are the facts? Again and again and again – what are the facts? Shun wishful thinking, ignore divine revelation, forget what “the stars foretell,” avoid opinion, care not what the neighbors think, never mind the unguessable “verdict of history” – what are the facts, and to how many decimal places? You pilot always into an unknown future; facts are your single clue. Get the facts!

The 3-legged stool of understanding is held up by history, languages, and mathematics. Equipped with those three you can learn anything you want to learn. But if you lack any one of them you are just another ignorant peasant with dung on your boots.

A generation which ignores history has no past — and no future.

Around the time of the Terran Caesar Augustus, a Martian artist had been composing a work of art. It could have been called a poem, a musical opus, or a philosophical treatise; it was a series of emotions arranged in tragic, logical necessity. Since it could be experienced by a human only in the sense in which a man blind from birth might have a sunset explained to him, it does not matter which category it be assigned.