Riddle of the stones

The Stonehenge he describes is not artificially compressed into a single space and time. For there is not one Stonehenge but many - three major construction phases in prehistoric times, taking place over the course of a millennium. Nor does it stand aloof and alone for it is part of a wider story, its hyphens and full stops the avenues and henges that punctuate the Neolithic landscape.

So what exactly is Hengeworld? A time between four and five thousand years ago and a place where people were radically altering their environment by constructing huge earthwork enclosures (henges), stone circles and rings of wooden posts. Stonehenge may stand by the roadside as the emblem of this lost world, yet this Neolithic transformation has largely been overridden by the successive legacies of later eras from the Bronze Age barrows and Roman roads to our modern motorways and power lines.

There are many cultural layers to be stripped back before the hidden world beneath is revealed, the "underground Stonehenge" that is the domain of archaeologists. In the last century, one year out of every three saw excavations at Stonehenge - many of them poorly or partly published. It was only recently, thanks to English Heritage, that the results of these past digs have become available. As Pitts shows, making sense of the pits, holes and trenches made by past archaeologists is almost as bewildering a task as interpreting the ditches, mounds and megalithic stones of our prehistoric ancestors.

So the Hengeworld that is reconstructed in this book, perhaps inevitably, is peopled as much by archaeologists, farmers, and telephone technicians laying cables (with the occasional modern Druid thrown in for good measure) as it is prehistoric man. Despite the large number of human remains unearthed in and around the monument, only one Neolithic individual emerges out of the communal charnel house - the digitally reconstructed face of "Stonehenge Man".

The recent discovery of Seahenge on the Norfolk coast - a timber ring consisting of more than 50 posts surrounding an upturned oak stump - is a powerful reminder that the Neolithic, or New Stone Age, was not all about stone. Constructing timber circles (like raising megaliths) involved concerted effort, manpower and raw materials. Close to Stonehenge is Woodhenge where some of the posts stood nine metres high and weighed more than five tons. A Neolithic wooden palisade recently excavated in Powys enclosed an amazing 34 hectares - this was no picket fence.

Wales has long played a role in the Stonehenge story - as the source of the megalithic bluestones. Suddenly, and fleetingly, towards the end of the book the grand Neolithic drama is outlined. At Hengeworld the great stones are the embodiment of the ancestors and the realm of the dead. Mighty oak totem poles are the emblems of the living and the recently departed. The bluestones are brought by land and sea from the Preseli hills, from the west, the land of the dead and the midwinter sunset. The much-debated astronomical alignments of Stonehenge fall into place. Mass funerary processions begin at Woodhenge, in the domain of the living, land of the rising sun and reach a crescendo at Stonehenge itself, the hub where "East meets West, stone wood, ancestor the new dead".

It is remarkable that what is perhaps the best known cluster of Neolithic monuments and earthworks in the world still withholds so much of its mystery. In the midst of Hengeworld stands the silent enigma of Silbury Hill - a man-made creation estimated to have taken eight times the manpower required to dig the Avebury henge. As Pitts rightly says, a new excavation of Silbury is overdue, it is time to dig another time tunnel into the unique ancestral landscape of Hengeworld.