Jason Robards
Narrator (voice)
Red Barber
Self - Radio Announcer
Erik Barnouw
Self - Historian
Ken Bilby
Self - Biographer of David Sarnoff
Norman Corwin
Self - Writer
Susan Douglas
Self - Historian
Frank Günther
Self - Engineer
Jeanne Hammond
Self - Niece of Edwin H. Armstrong
Loren Jones
Self - Engineer
Garrison Keillor
Self - Writer
Helen Kelley
Self - Radio Broadcaster
Robert Morris
Self - Engineer
Dana Raymond
Self - Friend of Edwin H. Armstrong
Gertrude Tyne
Self - Engineer
Fred Allen
Self - Predicts Demise of Radio (archive footage)
Gene Autry
Self - Sings (archive sound)
John Barrymore
Hamlet (archive sound)
Winston Churchill
Self - Finest Hour Speech (archive sound)
Charles J. Correll
Self - Prepares for Amos 'n' Andy Broadcast (archive footage)
Lee De Forest
Self - Objects to Quality of Radio Programming (archive footage)
Ralph Edwards
Self - Host of 'This Is Your Life' (archive footage)
Dwight D. Eisenhower
Self - Announces Landing in Normandy (archive footage)
Eugenia Farrar
Self (with Lee De Forest) (archive footage)
Freeman F. Gosden
Self - Prepares for Amos 'n' Andy Broadcast (archive footage)
Guglielmo Marconi
Self - Visits Sarnoff at RCA (archive footage)
Marie Mosquini
Self - with Lee De Forest (archive footage)
Nelson Rockefeller
Self - Eulogizes Sarnoff (archive footage)
Franklin D. Roosevelt
Self - Makes Broadcast About Banking Reform (archive footage)
David Sarnoff
Self - with Marconi at RCA (archive footage)
Frank Sinatra
Self - Serenades Sarnoff (archive footage)
Arturo Toscanini
Self - Conducts NBC Symphony (archive footage)
Harry S. Truman
Self - Announces Bombing of Hiroshima (archive sound)
Bob Warren
Self - This is Your Life Announcer (archive footage)
Orson Welles
Self - Professor in War of the Worlds Broadcast (archive sound)