Yet the idea of New York as a walker’s paradise—a city best, and only authentically, grasped by sauntering through it—has persisted. Much of the great literature of New York has been written from the perspective of the sidewalk: the deafening street clatter and humming rattle of the L train that roar through John Dos Passos’s “Manhattan Transfer”; Ralph Ellison’s Invisible Man eating yams on a Harlem street corner and tasting freedom; the author Quinn in Paul Auster’s “City of Glass” realizing that the peregrinations taken around the city by his quarry spell out the words “Tower of Babel.”…You never need to ask New Yorkers where they’re going. They’re already there.