Human judges can show mercy. But against the laws of nature, there is no appeal.

Attempting to define science fiction is an undertaking almost as difficult, though not so popular, as trying to define pornography... In both pornography and SF, the problem lies in knowing exactly where to draw the line.

After their encounter on the approach to Jupiter, there would aways be a secret bond between them---not of love, but of tenderness, which is often more enduring.

The more wonderful the means of communication, the more trivial, tawdry, or depressing its contents seemed to be.

But please remember: this is only a work of fiction. The truth, as always, will be far stranger.

Sometimes when I'm in a bookstore or library, I am overwhelmed by all the things that I do not know. Then I am seized by a powerful desire to read all the books, one by one.

Using material ferried up by rockets, it would be possible to construct a "space station" in ... orbit. The station could be provided with living quarters, laboratories and everything needed for the comfort of its crew, who would be relieved and provisioned by a regular rocket service. (1945)