Walter Shapiro, a journalist about to leave Washington for a magazine job in New York, departs with a warm glow about a D.C. cab driver--so warm, he said, that "it makes up for a helluva lot of parking tickets" and other aggravations during his time here.

Shapiro, wearing the chocolate brown Borsalino hat his wife bought him in Rome, took a cab the other night from Georgetown to a Northwest apartment building for dinner. Next day he realized the hat was missing. His dinner hostess checked and said he hadn't left the hat there.

So Shapiro called one D.C. taxicab office listed in the city phone book. He was referred to another number. He told the woman who answered that the cab exterior bore the name of the hacker, Khan, and he thought the first name started with a Z.

A fortunate, if unlikely, combination. The woman checked her computer, came up with the name of Zar Khan and a telephone number. Two calls and Shapiro reached the cabbie. "I would have returned the hat but I didn't know your name and address," Khan told Shapiro. That afternoon he dropped the hat at Shapiro's office, getting a near-record tip for his efforts: $20.