Two of the most experienced researchers into prehistoric culture have made a remarkable breakthrough in understanding the system by which prehistoric monuments were designed and placed on the landscape. This system, a precision geodetic science, enabled the megalith builders to mark out vast geometric shapes across the landscape. At key points, they erected their magnificent stone temples and markers, whose dimensions and locations encoded their knowledge of the Earth and sky. Long trackways, stone rows, stone circles, standing stones and huge earthworks—monuments dating back well over four thousand years—have held on to their secrets despite centuries of investigation. Now, Michell and Heath show that  Prehistoric Britons knew the dimensions of the Earth and had undertaken an accurate survey of the British Isles, pre-3000 BC; the major time periods of the Sun and Moon were encoded within their monuments, measures and system of land surveying; and that this prehistoric system was still being applied in the Middle Ages, and remnants survive today.  Illustrated.  Published in England as The Measure of Albion.