Behind every man now alive stand thirty ghosts, for that is the ratio by which the dead outnumber the living.

You don't believe in organized religion, yet a major theme in so many of your works seems to be a quest for God.

A well-stocked mind is safe from boredom.

In my life I have found two things of priceless worth - learning and loving. Nothing else - not fame, not power, not achievement for its own sake - can possible have the same lasting value. For when your life is over, if you can say 'I have learned' and 'I have loved,' you will also be able to say 'I have been happy.

Guns are the crutches of the impotent.

New ideas pass through three periods: 1) It can't be done. 2) It probably can be done, but it's not worth doing. 3) I knew it was a good idea all along!

And because, in all the Galaxy, they had found nothing more precious than Mind, they encouraged its dawning everywhere. They became farmers in the fields of stars; they sowed, and sometimes they reaped. And sometimes, dispassionately, they had to weed.