Mother Nature doesn't care if you're having fun.

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.

How the mind works, by what strange paths it pursues memory.

It's called the Santa Claus effect; the holiday period is traditionally a strong cycle.

In writing biography, fact and fiction shouldn't be mixed. And if they are, the fictional points should be printed in red ink, the facts printed in black ink.

I'm not really looking forward to wearing a black rubber suit in the summertime in humid Chicago. If you see a pool of sweat through the city, follow it and you will find me.

Don't throw away your conscience.

There are three great events in our lives: birth, life and death. Of birth we have no conscience; with death, we suffer; and, concerning life, we forget to live it.

Your culture is your limit; if you can't go beyond it, you will remain as a frog of your little lake!

All artists are illusionists of one kind or another.

People forget that actors are actors, who are looking to put on the clothes and the character, and then shed it just as easily.

When you take a pitch and line it somewhere, it's like you've thought of something and put it with beautiful clarity.