Fredric Brown, Hall of Mirrors
“ There is nothing to fear, but much to explain. Much that you must understand before the time lock opens that door. Much that you must accept and—obey."You have already guessed that you are in the future—in what, to you, seems to be the future. The clothes and the room must have told you that. I planned it that way so the shock would not be too sudden, so you would realize it over the course of several minutes rather than read it here—and quite probably disbelieve what you read."The 'closet' from which you have just stepped is, as you have by now realized, a time machine. ”
