Barley expressed the hope that this year's Book Festival will help readers and writers of all ages to think about and discuss how to act positively upon the understanding generated by dialogue.
The sold-out events include American novelist George Martin, author of the Game of Thrones series, and Japanese writer Haruki Murakami, who makes his first trip to Edinburgh to launch the English edition of his latest novel Colorless Tsukuru Tazaki and His Years of Pilgrimage.
As the Scottish independence referendum was scheduled for Sept. 18, Scottish First Minister Alex Salmond and former British Prime Minister Gordon Brown were also set to discuss the past, present and future of Scotland at the Book Festival.
The Edinburgh International Book Festival began in 1983 and is now a key event in the August Festival season, celebrated annually in Scotland's capital city. Biennial at first, the Book Festival became a yearly celebration in 1997.
Programming over 700 events, the Book Festival attracts around 220,000 visitors each year at gardens transformed into a magical tented village.
This year's Book Festival is to close on Aug. 25.