In challenging a kzin, a simple scream of rage is sufficient. You scream and you leap.

Ethics change with technology.

SF isn't a genre; SF is the matrix in which genres are embedded, and because the SF field is never going in any one direction at any one time, there is hardly a way to cut it off.

The human species really could have faced global thermonuclear war. During seventy years of Cold War we grew used to it.

Everything starts as somebody's daydream.

In the world of words the imagination is one of the forces of nature.

In hindsight it may even seem inevitable that a socialist society will starve when it runs out of capitalists.

You learn by writing short stories. Keep writing short stories. The money's in novels, but writing short stories keeps your writing lean and pointed.

We learn only to ask more questions.

It's very difficult for a black man to get out of South-Central Los Angeles, and get out civilized....The only men I know who have escaped, all began reading Robert Heinlein at age ten.

One mark of a good officer, he remembered, was the ability to make quick decisions. If they happen to be right, so much the better.

Shyness is just egoism out of its depth.

I have found no other cure for loneliness than to befriend it.

Beneath the eerie calm of these unfathomable waters were deadly whirlpools of ambition, anger and unhappiness.

What you see is news what you know is background what you feel is opinion.

For better or worse, poetry is my life.

Sometimes I pay for it, With the way I walk now, the things I did to my body wasn't supposed to be done. At 48 years old, it is saying, 'Hey, Earl, remember what you did to me?'.

The better proof of reverence for that holy name would be not to profane it by making it a topic of legislative discussion.

If you would get a contented life, do not grasp too much of the world, do not take in more of the business of the world than God calls you to.

Leading a human life is a full-time occupation, to which everyone devotes decades of intense concern.

Learning is its own exceeding great reward; and at the period of which we speak, it bore other fruits, not unworthy of it.