Christopher Knight and Alan Butler establish conclusively that even before the last ice age an advanced civilization existed that had knowledge of Megalithic and metric measuring systems and of the Earth's size--and that fragments of this culture were preserved. They explain how the oldest, most enigmatic of the Neolithic monuments--the henges of North Yorkshire--were planned, what their purpose actually was, what amazing connection they have to the later Pyramids of Giza, and why both henges and pyramids are earthly representations of the stars in Orion's belt.