Before the current decade ends, fee-paying passengers will be experiencing suborbital flights aboard privately funded vehicles. . . . It won't be too long before bright young men and women set their eyes on careers in Earth orbit and say: "I want to work 200 kilometers from home-straight up!"

If we have learned one thing from the history of invention and discovery, it is that, in the long run-and often in the short one-the most daring prophecies seem laughably conservative.

Guns are the crutches of the impotent.

Some things have eternal value, and compassion is one of them. I hope we never lose that. Compassion for humans as well as animals.

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

Belief in God is apparently a psychological artifact of mammalian reproduction.

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.