THE Edinburgh International Book Festival, which begins today, starts with a day full of sold-out events and with ticket sales off to a "very good start", its director said.

Events that have sold out on the first day of the annual festival include appearances by Kate Atkinson, Salman Rushdie, Alexander McCall Smith and Joy Division bassist Peter Hook.

Nick Barley, director of the festival, said events such as Alasdair Gray's appearance on August 14, where the author and artist will discuss his controversial 'Settlers and Colonists' essay, will provide a valuable platform for public debate.

"A lot is made of the economic contributions that the festivals make to Edinburgh and Scotland, but I am even more proud of the intellectual contribution," he said.

"The Alasdair Gray event is a case in point.

"That should be an interesting session.

"But there is also the chance to discuss independence and it is very difficult at times to have a sensible debate, certainly in 140 characters on Twitter.

"What we need is more debate to really get into some of the ideas involved."

Mr Barley said he felt optimistic about this year's festival, which features a look at graphic novels and a celebration of its 30th birthday, as well as appearances by Andrew Marr, Neil Gaiman, Ian Rankin, Margaret Atwood and many more. There will also be a special event to celebrate the life and work of the late Iain Banks, the Scottish writer who died this year.

This year's festival takes place in Charlotte Square and involves a total of eight theatres as well as a full programme of children's events.