When Julian Spalding was head of museums in Glasgow, he certainly left his mark, as he helped found both the Gallery of Modern Art or Goma, as well as the St Mungo Museum of Religious Art and Life.

His choice of art for Goma was controversial in its time, and so, perhaps will be his latest theory. Since he left running museums in 1999, Mr Spalding has been an art critic, writer and theorist, and in his latest tome, Realisation: From Seeing to Understanding, he posits a new theory about one of Scotland - and the world's - most important archaeological sites. Skara Brae, in the Orkney Islands, has, since its discovery in 1850, been regarded as a key Neolithic site. It has given generations of scholars invaluable insights into how our distant ancestors lived. It has long been regarded as a series of dwellings.

Not so, Mr Spalding says. He believes that the stone rooms are a cluster of "sacred saunas" where the inhabitants of Mainland would gather to be heated by steam baths and commune with the spirits of the dead. It's a novel idea albeit one, perhaps, that will take some time - although perhaps not 5000 years - to seriously challenge the orthodox view of these extraordinary remains.