Former building engineer Simon Mallon, of Frome, enjoyed a 40-year career before turning his hand to writing.
His latest novel On the Edge of the Blue gives a fascinating explanation of how and why Stonehenge was built.
Mr Mallon said: "The sheer effort expended by the constructors of the first Stonehenge suggests Europe's most iconic ancient structure was created for a magnificent purpose. But what purpose?
"Astrological, mathematical, medical, all laudable ideas based on nothing more than guesswork and hunches and so very wrong.
"Stonehenge is older than it looks, it was built to defeat the greatest threat mankind ever faced, the Ice Age and it succeeded."
Mr Mallon believes that the henge stood on the side of a massive lake, and that the Preseli stone that was used to build it was brought across the frozen sea from the Pembrokeshire mountains to Bristol and then on across the lake.