The dinosaurs disappeared because they could not adapt to their changing environment. We shall disappear if we cannot adapt to an environment that now contains spaceships, computers - and thermonuclear weapons.

Look, whispered Chuck, and George lifted his eyes to heaven. (There is always a last time for everything.) Overhead, without any fuss, the stars were going out.

There is hopeful symbolism in the fact that flags do not wave in a vacuum.

If an elderly but distinguished scientist says that something is possible, he is almost certainly right; but if he says that it is impossible, he is very probably wrong.

Even by the twenty-second century, no way had yet been discovered of keeping elderly and conservative scientists from occupying crucial administrative positions. Indeed, it was doubted if the problem ever would be solved.

I don't believe in God but I'm very interested in her.

Floyd could imagine a dozen things that could go wrong; it was little consolation that it was always the thirteenth that actually happened.