Do not forget that a traitor within our ranks, known to us, can do more harm to the enemy than a loyal man can do good to us.

Arthur Clarke says that I am first in science and second in science fiction in accordance with an agreement we have made. I say he is first in science fiction and second in science.

Unfortunately, in many cases, people who write science fiction violate the laws of nature, not because they want to make a point, but because they don't know what the laws of nature are.

While he lives, he must think; while he thinks, he must dream.

It took me thirty-six years; and, in some fifty stories, ranging in length from short-shorts to novels, I think I must have touched, in one way or another, on every aspect of computers and computerization. And (mark this!) I did it without ever knowing anything at all about computers in any real sense. To this day, I don't. I am totally inept with machinery... on my typewriter I turn out books at the contemptible rate of one a month

Tell me why the stars do shine, Tell me why the ivy twines, Tell me what makes skies so blue, And I'll tell you why I love you. Nuclear fusion makes stars to shine, Tropisms make the ivy twine, Raleigh scattering make skies so blue, Testicular hormones are why I love you.

Science is a mechanism, a way of trying to improve your knowledge of nature. It's a system for testing your thoughts against the universe, and seeing whether they match.