Aiming to find ghostly truth.
Nine researchers, helped by more than 200 members of the public, will use sophisticated equipment in the hope of recording ghostly activity in Edinburgh.
They will be monitoring whether anything is lurking in the dungeons of Edinburgh Castle, the vaults under South Bridge and Mary's King Close, a disused underground street in which hundreds of plague victims were sealed up and left to die.
The findings will be unveiled on April 17, the final day of Edinburgh International Science Festival.
However, Dr Richard Wiseman, a psychologist from the University of Hertfordshire, who is leading the investigation, admitted he was sceptical about the existence of ghosts.
"I'm a sceptic but if I see a ghost walking through the wall, then I'm prepared to be converted," he said.
The science festival runs from tomorrow until April 17.