People who think they know everything are a great annoyance to those of us who do.

Suppose that we are wise enough to learn and know - and yet not wise enough to control our learning and knowledge, so that we use it to destroy ourselves? Even if that is so, knowledge remains better than ignorance.

Having reached 451 books as of now doesn't help the situation. If I were to be dying now, I would be murmuring, "Too bad! Only four hundred fifty-one." (Those would be my next-to-last words. The last ones will be: "I love you, Janet.") [They were. -Janet.]

There is not a discovery in science, however revolutionary, however sparkling with insight, that does not arise out of what went before.

The intelligent man is never bored.

God, how that stings! I've spent a lifetime loving science fiction and now I find that you must expect nothing of something that's just science fiction.

Once, when a religionist denounced me in unmeasured terms, I sent him a card saying, "I am sure you believe that I will go to hell when I die, and that once there I will suffer all the pains and tortures the sadistic ingenuity of your deity can devise and that this torture will continue forever. Isn't that enough for you? Do you have to call me bad names in addition?"