Did a secret book fuel a witch-hunting frenzy in Europe?

An episode of the Deja Vu series traces how media have spread conspiracy theories over the past 600 years. The printing press helped fuel European witch-hunts while also helping usher in the Enlightenment. The programme also examines the Nazis’ use of radio for mass persuasion and how social media gave dictators new tools of control, before considering what artificial intelligence could bring next.