It's been disrupted by the Internet, but a century ago, radio was the great disrupter.
And the early days of radio as a mass medium were chaotic, with some major powerful figures emerging. Among them were David Sarnoff, the head of RCA, and inventor Edwin Armstrong.
The story of these friends-turned-enemies is at the center of Scott Woolley's book The Network: The Battle for the Airwaves and the Birth of the Communications Age. We return to our interview with the author from 2016.