For more than 30 years it has attracted the world’s leading authors to the historic heart of the Scottish capital.
Now the Edinburgh International Book Festival is set to undergo the biggest shake-up in its history after being forced to scale back its use of Charlotte Square Gardens.
The event, first staged in 1983, is set to spill out onto nearby George Street for the first time after agreeing to reduce its impact on the 200-year-old New Town space.
The main festival site will be redesigned to ensure the gardens can be used for other events, which is said to be impossible at present.
The owners of properties around the gardens said their annual use by the festival has taken a “heavy physical toll” on the space.
They are planning £1 million worth of improvements, including new landscaping, which will mean there will be less space for the book festival each August.
It hosted just 30 events in its first year, but has grown hugely in popularity since it became an annual event in 1997, with more than 800 guests in last year’s programme and a record 230,000 people flocking to the gardens.
However the owners are concerned about a “gradual deterioration” of the gardens due to the length of time it takes to recover from the 18-day event.
The book festival has been in talks with Edinburgh City Council and business group Essential Edinburgh over taking over the section of George Street between Charlotte Square and Castle Street in August.
The potential move has emerged just days after it was revealed that Fringe shows are likely to be ousted from St Andrew Square, at the other end of George Street, this summer due to concerns about the impact they have had on its garden.
The £1 million improvement plan for Charlotte Square Gardens is expected to see proper drainage and power facilities installed, as well as pathways and other new features. However, unlike St Andrew Square, public access is only expected to be approved for occasional events.
A spokesman for the Charlotte Square Proprietors Association said: “We’ve welcomed the book festival since it first took place in the gardens, providing it at no cost, and we strongly support its continued use by the festival.
"We also recognise the heavy physical toll the festival takes on the gardens prevents them from potentially being used for other public events and festivals.
“We’ve been working closely with the book festival to develop a management plan which will ensure its sustainable future within the gardens, and the gardens themselves, and would allow other events to take place.
"This is a complex exercise, but both parties are fully committed to coming up with an attractive, affordable and sustainable answer.
“There is categorically no threat to the continued presence of the book festival in the gardens. Instead, it is everyone’s ambition to find ways to introduce other events into this historic space.”
Book festival director Nick Barley said: “Over the last 33 years the book festival has become ever more internationally successful and welcomes more authors in more events, and growing audience numbers, each year.
"In order to maintain our position as the world’s leading public celebration of words and ideas we must look to continually innovate and evolve.
“We’ve been working closely with the proprietors, who generously make the gardens available each year, but who have now asked us to reduce our impact on this private space.
"We’re exploring different physical configurations to find a way that the festival’s ambitions and use of the gardens are compatible with the needs of the owners, while retaining the elements of this world-class festival that our authors and audiences love.
“This year, we’re looking at ways of improving our infrastructure to ensure a quicker get-in and get-out to minimise damage to the turf and soil.
"We’re also in discussion with the city council and Essential Edinburgh to look to expand into new spaces on George Street, which will open up the festival to new audiences.”
Roddy Smith, chief executive of Essential Edinburgh, said: "We're hopeful that the book festival will be able to expand its footprint onto the west end of George Street for this year.
"We're working through a draft plan that will put to the council in a couple of weeks. We don't know the exact mechanics of it yet, but we're trying to provide a space for them.
"We're very supportive of the idea, as it's a great event that draws a lot of people to the area. It would have very low impact on George Street. It's a logical way go if the book festival needs more space.
"I think the Charlotte Square owners want to have the potential to host other smaller events in there now and again. It's never going to be the intention to open it up as a big events space. It's not just about the size and scale of the book festival, the garden just isn't built for it. It's just soil with grass on top."
A spokeswoman for the city council added: “Our discussions are ongoing with the Edinburgh International Book Festival to explore additional opportunities to support their plans in 2017.”