Considering what human beings do and have done to human beings (and to other living things as well) ... I can never imagine what the devil people think computers can add to the horrors.

Writing is a lonely job. Even if a writer socializes regularly, when he gets down to the real business of his life, it is he and his type writer or word processor. No one else is or can be involved in the matter.

Grip the nettle firmly and it will become a stick with which to beat your enemy.

A robot must obey the orders given it by human beings except where such orders would conflict with the First Law. [The Second Law of Robotics]

Old men tend to forget what thought was like in their youth; they forget the quickness of the mental jump, the daring of the youthful intuition, the agility of the fresh insight. They become accustomed to the more plodding varieties of reason, and because this is more than made up by the accumulation of experience, old men think themselves wiser than the young.

Every period of human development has had its own particular type of human conflict---its own variety of problem that, apparently, could be settled only by force. And each time, frustratingly enough, force never really settled the problem. Instead, it persisted through a series of conflicts, then vanished of itself---what's the expression---ah, yes, 'not with a bang, but a whimper,' as the economic and social environment changed. And then, new problems, and a new series of wars.

At two-tenths the speed of light, dust and atoms might not do significant damage even in a voyage of 40 years, but the faster you go, the worse it is--space begins to become abrasive. When you begin to approach the speed of light, hydrogen atoms become cosmic-ray particles, and they will fry the crew. ...So 60,000 kilometers per second may be the practical speed limit for space travel.