The wild and rugged west coast of Ireland is one of the most luminous places on earth, and Sligo, in the northwest, is the epitome of wonder, a mystical region of transcendent beauty, where spirits inhabit waterfalls, mountains, trees and air. Sligo is also a land of scholars and saints, a land steeped in history that is centuries old. One has only to visit there to understand why it became so beloved by the poet William Butler Yeats. After passing...