Granite, a tough composite of quartz, feldspar and mica, is the stuff of Dartmoor, the most formidable of the five granite bosses punctuating Britain's southwest peninsula. A miserable place of rain and bog or a sunny upland of exquisite natural beauty, here the elements are raw, the sky huge and nature seems ascendant.

But it is no less a place made by human beings. Stone circles, crosses, dwellings and boundaries speak of the ancient, medieval and modern people that extracted a living from the moorscape and created what it is today. Where convicts are incarcerated, backpackers roam freely; where commoners graze livestock, the army is trained; where the National Park Authority exercises control, the Duchy of Cornwall claims ownership. And Dartmoor remains a place that provides. Reservoirs hold the water drunk by local people. China clay is extracted from its mineral reserves. Not long ago granite was quarried from its hillsides.

What is modern Dartmoor and what should it be? Did druids officiate here? Can the bog be drained and crops grown? Is it the place for a prison? And what of its people's future, and the fate of its ponies, cows and sheep? For three hundred years such questions have been asked of the moor. Quartz and Feldspar does not so much provide answers as unearth those who did and the arguments they provoked.