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)