We all love a good conspiracy theory: 9/11 was an inside job; the moon landings were faked; Princess Diana was assassinated. There is a thrill in joining the dots between seemingly random events and discovering hidden patterns. As the University hosts Edinburgh Spy Week, the annual event that examines espionage fiction and film and the ways in which secrecy runs through culture, the organisers ask why such theories have such a pull on the imagination, and what happens when they are elevated to the status of historical truth. They discuss the surprising origins of President Trump's post-truth world and the layers of nostalgia within John le Carre's masterpiece of spy fiction, Tinker Tailor Soldier Spy.