Good morning, Dr. Chandra. This is Hal. I am ready for my first lesson.

It may be that our role on this planet is not to worship God - but to create him.

Can the synthesis of man and machine ever be stable, or will the purely organic component become such a hindrance that it has to be discarded?

The dinosaurs disappeared because they could not adapt to their changing environment. We shall disappear if we cannot adapt to an environment that now contains spaceships, computers - and thermonuclear weapons.

It may be that the old astrologers had the truth exactly reversed, when they believed that the stars controlled the destinies of men. The time may come when men control the destinies of stars.

It must be wonderful to be seventeen, and to know everything.

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!"