Back in 1952, the great American science fiction writer Ray Bradbury published a short story called “The Pedestrian” in a small antifascist publication. The story, which was based on Bradbury’s own experience of being hassled by the cops while walking the streets of Los Angeles, imagined a world in which automobile dominance was so complete that walking for any purpose would be seen as a sign of mental illness. We take a look back at Bradbury’s dystopian vision, and talk with four people — paleoanthropologist Jeremy DeSilva and writers Garnette Cadogan, David Ulin and Antonia Malchik — about how walking contributes to our essential humanity, and what we lose when we build environments that make it impossible for people to walk