"Radio Estados Unidos Historia" . . "Radio États-Unis Histoire." . . "Ràdio Estats Units d'Amèrica Història." . . "Radio États-Unis Biographies." . . . . "Biographies of three pioneers in the radio field who turned a hobby into radio and launched the modern communications age." . . . . . "Empire of the air The men who made radio" . . . . . . . . "Empire of the air : the men who made radio" . "Empire of the air : the men who made radio"@en . "History"@en . "History" . "Biographies" . . . . "Biography"@en . "Biography" . "This is the story of three American pioneers of radio - Lee de Forest, inventor of the vacuum tube; Edwin Howard Armstrong, creator of transmitter and amplification devices and the FM system; and David Sarnoff, who made RCA into a corporate giant. The author also chronicles the development of radio from a primitive wireless communication system to its golden age in the 1930s and 1940s." . . . . . . . . "Empire of the air the men who made radio" . "Empire of the air the men who made radio"@en . . . . . . . . . . . "Biographie." . . "Radio." . . . . "Ràdio Estats Units d'Amèrica Biografia." . .