“The best evidence that time travel is impossible is the fact that we haven't been invaded by hordes of tourists from the future.”

“The distinction often seems precarious. Both traveler and tourist are, by definition, separate from their environment. We like to think that the role we aspire to, the traveler, has that distance on the scene that implies vision and understanding, while the tourist suffers the alienation of the passive viewer, the "sightseer." At its worst, tourism is felt to represent a moral or spiritual failing. And in our hear we fear that we, too, are tourists.”

“There comes a time when we can no longer tell the invaders from the invaded. That is what we call "War.”

“The very existence of libraries affords the best evidence that we may yet have hope for the future of man”

“Tourists don't know where they've been, travelers don't know where they're going.”

“Tourists went on holidays while travellers did something else. They travelled.”