Sir Anthony Hopkins discussed psychic ability and synchronicity with director Scott Hicks in an interview included on the DVD. In that exchange, he tells how he had been in Florence, filming Hannibal (2001), and reading a non-fiction book by William Goldman. In the book, Goldman discussed previously working with Hopkins, and discussed Kathy Bates in Misery (1990). Hopkins recalled thinking that it would be interesting to work with Goldman again, and it would be interesting to work on a Stephen King story. Two days later, a call came that there was a script for him to read, by Goldman, based on a King story. Hopkins accepted immediately.
Director Scott Hicks mentioned (commentary at 01:31:46) that the "11" on the window after the flashback ends, was meant to tell the viewer that Bobby Garfield recalled the entire flashback in only eleven seconds of real-time, before the condensation on the window evaporated.
Director Scott Hicks said that one of the hardest things of all was to get Anton Yelchin (Bobby) to laugh in the scene where Sir Anthony Hopkins (Ted) imitates a fart (commentary at 14:55). Anton was raised in an atmosphere where laughing with an open mouth was impolite, so it was not natural for him to do so, even when, during Anton's close-up of the shot, Hopkins barked like a dog. Anton was not enjoined from grinning, such as from 48:41 to 48:42 where, in an "off-camera" moment, the camera caught him grinning after Scott had said "cut", and the filmmakers liked the effect.
The story on which this movie was based originally contained references to Stephen King's "The Dark Tower" series, which is set in multiple parallel universes, some resembling our own, but others having high fantasy and/or steampunk settings. The character of Ted Brautigan appeared in King's seventh and final Dark Tower novel, "The Dark Tower". In that novel, the full extent of Ted's psychic power is shown. At one point, he leads several other characters into a closet, from which he transports them to a far-off land. One character explicitly compares this to the wardrobe from "The Chronicles of Narnia", by C.S. Lewis. Sir Anthony Hopkins played Lewis in Shadowlands (1993). C.S. Lewis also wrote an unfinished novel titled "The Dark Tower".