The Edinburgh International Book festival has begun its 16-day residence in the city’s Charlotte Square Gardens. More than 800 authors from 45 countries will be appearing at about 750 events during the festival. Festival director Nick Barley promised “an Olympics of the mind” with top authors discussing big ideas. Half of the 12 authors long-listed for the 2012 Man Booker Prize will be appear at the festival. Ned Beauman, Michael Frayn, Deborah Levy, Hilary Mantel, Will Self and Jeet Thayil will all showcase their work in Edinburgh. Also appearing will be Zadie Smith, Howard Jacobson and Pat Barker.