In the so-called golden age of radio, Americans gathered around hulks of mahogany with Bakelite knobs and vacuum tubes and listened to dramas and comedies. Tens of millions of people heard F.D.R.’s fireside chats; seventy million listened to Joe Louis clash with Max Schmeling. By the fifties, television had seized the mass audience. Bob Hope migrated to the screen. Radio became a medium for the road and the solitary listener: the long-haul trucker fighting off sleep, the commuter stuck in traffic.journey-inline-newsletterinline-newsletter