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

“There's no real objection to escapism, in the right places... We all want to escape occasionally. But science fiction is often very far from escapism, in fact you might say that science fiction is escape into reality... It's a fiction which does concern itself with real issues: the origin of man; our future. In fact I can't think of any form of literature which is more concerned with real issues, reality.”

“...science fiction is something that could happen - but usually you wouldn't want it to. Fantasy is something that couldn't happen - though often you only wish that it could.”

“Much blood has also been spilled on the carpet in attempts to distinguish between science fiction and fantasy. I have suggested an operational definition: science fiction is something that COULD happen - but usually you wouldn't want it to. Fantasy is something that COULDN'T happen - though often you only wish that it could.”

“Politicians should read science fiction, not westerns and detective stories.”

“["The Devil in the Dark"] impressed me because it presented the idea, unusual in science fiction then and now, that something weird, and even dangerous, need not be malevolent. That is a lesson that many of today's politicians have yet to learn.”

“Now, before you make a movie, you have to have a script, and before you have a script, you have to have a story; though some avant-garde directors have tried to dispense with the latter item, you'll find their work only at art theaters.”