“There never can be a man so lost as one who is lost in the vast and intricate corridors of his own lonely mind, where none may reach and none may save.”

“When asked for advice by beginners. Know your ending, I say, or the river of your story may finally sink into the desert sands and never reach the sea.”

“Do you know what it is to play a part? To split your personality deliberately for twenty-four hours a day? Even when with friends? Even when alone, so that you will never forget inadvertently? To be a dilettante? To be eternally amused? To be of no account? To be so effete and faintly ridiculous that you have convinced all who know you of your own worthlessness? All so that your life may be safe even though it means it has become barely worth living. But even so, once in a while I can fight them.”

“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.”

“Individual science fiction stories may seem as trivial as ever to the blinder critics and philosophers of today, but the core of science fiction -- its essence -- has become crucial to our salvation, if we are to be saved at all.”

“The Three Laws of Robotics:1: A robot may not injure a human being or, through inaction, allow a human being to come to harm;2: A robot must obey the orders given it by human beings except where such orders would conflict with the First Law;3: A robot must protect its own existence as long as such protection does not conflict with the First or Second Law;The Zeroth Law: A robot may not harm humanity, or, by inaction, allow humanity to come to harm.”

“A "simple aspect of science" may be defined as one which, through good fortune, I happen to understand.”