“If you could take one ride in a time machine, which way would you go? The future or the past? Sally forth or turn back?...Do you prefer the costumed pageant of history or the techno-marvels to come? It seems there are two kinds of people. Both camps have their optimists as well as their pessimists. Disease is a worry. Time traveling while black or female poses special hazards. Then again, some people see ways to make money at lotteries, stock markets, and racetracks. Some just want to relive past loves. Many back travelers are driven by regret—mistakes made, opportunities lost.”