A fanatic's willingness to kill or be killed in the service of a cause cannot prove the rightness of that cause.

Better a life like a falling star, brief bright across the dark, than the long, long waiting of the immortals, loveless and cheerlessly wise.

Colonization means potential immortality for the human genus. Man's safety on Earth was never great, and it dwindles hourly. Disarmament, even world government, will not guarantee survival in an age when population presses natural resources to the limit and when the knowledge of how to work mischief on a planetary scale is ever more widely diffused among peoples who may grow ever more desperate.

We live with our archetypes, but can we live in them?

What five books would I like to be remembered for? Well... Tau Zero, I like that one especially. It was somewhat of a tour de force, and I think it got across what I was trying for.

In Harvest of Stars, there is this notion, not original with me of course, that it will become possible to download at least the basic aspects of a human personality into a machine program.

I think the first duty of all art, including fiction of any kind, is to entertain. That is to say, to hold interest. No matter how worthy the message of something, if it's dull, you're just not communicating.