A terrible beauty is born, observed the greatest modern Irish poet after his country's 1916 Easter Rebellion against the British. This streak of proud nationalism, interwoven with elements of Celtic lore and mysticism, and infused with a hard-earned wisdom, makes Yeats's works resonate to this day. His career spanned five decades, earning him the Nobel Prize in Literature in 1923, and he is widely regarded as the finest English-language poet of...