The first time I visited New York, between 40 and 50 years ago, it was a place of ill repute, at least among foreigners. Rumor and report made the city sound like a low-intensity war zone, and you would find yourself regaled with advice on how to stay safe there, un-mugged and un-shot. On no account wander about at night, you were told, and if you insist on going out after dark, get into and out of your taxi at your point of departure and your destination, without deviating. Do not think of going to, or even passing through, Harlem. The rules to follow in New York were like an updated version of those followed by Transylvanian peasants in Dracula.