Isabel Hilton talks to Florian Henckel von Donnersmarck, director of The Lives of Others, winner of this year's Oscar for Best Foreign Language Film. Set in the German Democratic Republic, the film portrays a Kafkaesque world where the secret police, the Stasi, infiltrate every aspect of people's lives. Whereas some recent films about life in the Communist East have been touched with nostalgia, The Lives of Others creates a nightmare of surveillance. Plus reflections on the work of writer Primo Levi, 20 years after his death.