Why did it take centuries for St. John of the Cross to be declared a Doctor of the Church? As we approach the 100 year anniversary, we explore the surprising historical journey behind this recognition—from Spain's literary revival and the rise of mystical theology to the unexpected role of St. Thérèse of Lisieux and Pope Pius XI. Above all, we discover why St. John remains one of the Church's greatest guides to the spiritual life and why his teaching is more relevant than ever.