"Most people have heard of the Celts--the elusive, ancient tribal people who resided in present-day England, Ireland, Scotland and France. Paradoxically characterized as both barbaric and innocent, the Celts appeal to the modern world as a symbol of a bygone era, a world destroyed by the ambition of empire and the spread of Christianity throughout Western Europe. Despite the pervasive cultural and literary influence of the Celts, shockingly little...