To be a science fiction writer you must be interested in the future and you must feel that the future will be different and hopefully better than the present. Although I know that most - that many science fiction writings have been anti-utopias. And the reason for that is that it's much easier and more exciting to write about a really nasty future than a - placid, peaceful one.

What was more, they had taken the first step toward genuine friendship. They had exchanged vulnerabilities.

I have great faith in optimism as a guiding principle, if only because it offers us the opportunity of creating a self-fulfilling prophecy.

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

Finding intelligent life would encourage people and also of course the opportunity of learning a tremendous amount, but this is a danger. We might be so overwhelmed with knowledge and information, that we might be depressed or even become suicidal - because what's the point if they're thousands of years ahead of us? Why should we bother? - or become the ultimate couch potatoes.

1. When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong. 2. The only way of discovering the limits of the possible is to venture a little way past them into the impossible. 3. Any sufficiently advanced technology is indistinguishable from magic.

One theory which can no longer be taken very seriously is that UFOs are interstellar spaceships.