EARLY RADIO’S EFFECT AS A MASS MEDIUM On Halloween eve in 1938, Orson Welles’s radio dramatization of War of the Worlds (far left) created a panic up and down the East Coast, especially in Grover’s Mill, New Jersey—the setting for the fictional Martian invasion that many listeners assumed was real. A seventy-six-year-old Grover’s Mill resident (left) guards a warehouse against alien invaders.