I'm sure we would not have had men on the Moon if it had not been for Wells and Verne and the people who write about this and made people think about it. I'm rather proud of the fact that I know several astronauts who became astronauts through reading my books.

As his body became more and more defenseless, so his means of offense became steadily more frightful.

In this single galaxy of ours there are eighty-seven thousand million suns. [...] In challenging it, you would be like ants attempting to label and classify all the grains of sand in all the deserts of the world. [...] It is a bitter thought, but you must face it. The planets you may one day possess. But the stars are not for man.

I don't think there are any secrets to writing in the - everybody has their own techniques. You must be widely read, that's one thing, because you have to resolve a tremendous amount of background information. Also, you should know what the competition is writing, just so you're not wasting your time doing the same thing. Unless you do it better, of course.

Death focuses the mind on the things that really matter: why are we here, and what should we do?

There's a passage about 'rivers of molten rock that wound their way... until they cooled and lay like twisted dragon-shapes vomited from the tormented earth.' That's a perfect description: how did Tolkien know, a quarter century before anyone ever saw a picture of Io? Talk about Nature imitating Art.

I sometimes think that the universe is a machine designed for the perpetual astonishment of astronomers.