The medieval legend of the Grail, a tale about the search for supreme mystical experience, has never ceased to intrigue writers and scholars by its wildly variegated forms: the settings have ranged from Britain to the Punjab to the Temple of Zeus at Dodona; the Grail itself has been described as the chalice used by Christ at the Last Supper, a stone with miraculous youth-preserving virtues, a vessel containing a man's head swimming in blood; the Grail has been kept in a castle by a beautiful damsel, seen floating through the air in Arthur's palace, and used as a talisman in the East to...