I phoned the room, but there was no answer. At the front desk, the clerks assured me that I had the correct number, and that they had no idea where the guest might be. A security officer opened the room and confirmed that it was empty.

For mysterious reasons, guests occasionally wait downstairs. I wandered through the lobby and restaurants. With my beard, suit, and black bag, I look exactly like a doctor, and now and then my quarry jumps up and identifies themselves. Not this time.

“When do you plan to arrive?” asked a desk clerk who phoned an hour later, adding that my guest had been waiting in the lobby. When I spoke to the guest, he insisted that he’d “told the hotel” where he could be found. Guests respond badly to a suggestion that they pay for two visits, so I simply went back.