Happier are all men than the dwellers in Faerie – or the gods, for that matter…Better a life like a falling star, bright across the dark, than a deathlessness that can see naught above or beyond itself…the day draws nigh when Faerie shall fade, the Erlking himself shrink to a woodland sprite and then to nothing, and the gods go under. And the worst of it is, I cannot believe it wrong that the immortals will not live forever.

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.

There are some ideas so stupid that only intellectuals can believe in them, particularly left-wing intellectuals.

I wrote the first book, Harvest of Stars, and as I was writing it, I saw that certain implications had barely been touched on... It's perfectly obvious that two completely revolutionary things are going on, with cybernetics, and biological science.

He had seen too much of the cosmos to have any great faith in man's ability to understand it.

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 my considered opinion, the profit to be made by permanent settlement in space is nothing less than the survival of industrial civilization, and therefore the survival of nearly the entire human race, along with such amenities as peace, freedom, enough to eat, and the chance to reach a high age in good health.