When it comes to Einstein, leave the old guy alone! Leave the young guy alone, too, for that matter. History is populated with lunatics and geniuses, and everyone knows who they are. The new traveler will feel “The Itch” to visit history’s geniuses — it’s hard to fight that urge! Ease up on Einstein, be careful with Copernicus, and hands off Hawking! Give the T.A. a break and stay away from the high-profile personages. Everyone wants to be the first to reveal to Einstein that people eventually travel through time. The problem is, travelers have to land earlier and earlier in Einstein’s life to be the first to break the news. Telling a five-year-old Einstein that time travel happens is creepy. (A movement of radical zealots, “The First Steppers” insist that only by direct interference with Einstein & Co. does time travel become possible. These interferers are considered fanatics and have suffered the full justice of the crime courts.)