"That first novel of mine, Non-Stop, is directly attributable to Heinlein. His "Common Sense" seemed to me such a good story, but bereft of any human feelings. I thought long about that story, and then I thought how wonderful it would be to write about a spaceship in which people have been imprisoned for generations and to put in something of the human feeling. So that novel is directly attributable to Heinlein. I thought, in my youthful arrogance, that I could do it better — I didn't! I thought I could do it differently, and I think I did do it differently. And I suppose that on the whole, I've concentrated on doing things differently ever since."

“One of the characteristics of age was that all avenues of talk led backward in time.”

“You know that if you had been in charge of creation you would have found some medium less heart-breaking than Time to stage it in.”

“If you think with your emotions, slight glandular changes are sufficient to revise your entire outlook.”

“Why don’t you go somewhere quietly and consult your history books if you have no consciences to consult?”

“An overcrowded world is the ideal place in which to be lonely.”

“Frank II liked Spain. Philip's capital was gayer, warmer, and more sanitary than London. It was intoxicating to enjoy the best of both courts. It proved also extremely remunerative: the shared consciousness of Frank I and II was by far the quickest communicational link between the two rival countries, and as such was worth money. Not that Frank revealed his secret to a soul, but he let it be known he had a fleet of capable spies who moved without risk of detection between England and Spain. Burly Lord Burleigh beamed upon him. So did the Duke of Medina Sidonia.”