David Aaronovitch interviews Umberto Eco about his brilliant historical novel The Prague Cemetery set in 19th Europe, from Turin to Prague to Paris, at a time when conspiracies rule history. With his customary erudition and brilliance, Eco brings together Jesuits, Freemasons, Italian Republicans, French criminals and secret services, all linked by one single sinister villain. Eco and Aaronovitch talk about the Dreyfus affair and the Protocols of the Elders of Zion, conspiracies, scapegoats and anti-semitism.