... its main utility is in its usefulness for the time-traveler. Say your future self invents a time machine, and comes back to offer you a ride in it, say next week. Maybe the two of you want to visit the Renaissance, or maybe you're thinking Victorian. And maybe you want to stop and see the American Colonies on the way back, or drop in on a Sock Hop. I know what you're thinking - what do I wear? And more importantly, what do I wear under it?