The Prestige

A magician called Borden (at least in private) writes his own version of his life as a magician. There's a lot of focus on a trick, where he seems to move across any width of stage in an instant, and on a feud with another magician, Angier. The account includes passages, where he can't decide what exactly to write, arguing with himself. 3 generations later a Borden (at least biologically) learns about his ancestor. He's also convinced, he somehow has a twin brother, who's happy about this development.