While writing his latest novel, 11/22/63—which follows a young time traveler who attempts to stop Lee Harvey Oswald from killing John F. Kennedy—the author had to figure out how to make time travel work for him. And, in doing so, he codified some immutable temporal rules.
We've seen enough movies and read enough books to know that the way time travel works is different every time. When sending his hero, Jake Tapping, through a time bubble into 1963, King found his own guidelines:
"The more potential a given event has to change the future, the more difficult that event would be to change. If you wanted to go back and speak to somebody on a street corner so that they were five minutes late to an appointment—that might not be too hard. But if you wanted to stop the assassination of a president, that would be really difficult. The past would try to protect itself."
"The further back you go, the more precautions you have to take. It would go right to the language—you'd have to be careful about the way you speak; the accents would be different. If you were to return to, say, 1858, you'd really have to prepare ahead of time."
Simple enough, right? But working with time travel for one book was enough to make King swear off time travel:
"No, this is it. Absolutely not. No, that's done. It's like Apollo Creed says, 'Ain't gonna be no rematch.'"