Cabdrivers and their yellow taxis are as much a part of the cityscape as the high-rise buildings and the subway. We hail them without thought after a wearying day at the office or an exuberant night on the town. And, undoubtedly, taxi drivers have stories to tell—of farcical local politics, of colorful passengers, of changing neighborhoods and clandestine shortcuts. No one knows a city's streets—and thus its heart—better than its cabdrivers. And from behind the wheel of his taxi, Dmitry Sa...