When Christopher Somerville set out to explore Britain's cathedrals, he found his fixed ideas shaken to the roots. Starting out, he pictured cathedrals--Britain possesses more than 100--as great unmoving bastions of tradition. But as he journeys among favorites old and new, he discovers buildings and communities that have been in constant upheaval for 1,000 years. Here are stories of the monarchs and bishops who ordered the building of these massive...