Canticle For Leibowitz by Walter Miller

In the depths of the Utah desert, long after the Flame Deluge has scoured the earth clean, a monk of the Order of Saint Leibowitz has made a miraculous discovery: holy relics from the life of the great saint himself, including the blessed blueprint, the sacred shopping list, and the hallowed shrine of the Fallout Shelter.

In a terrifying age of darkness and decay, these artifacts could be the keys to mankind's salvation. But as the mystery at the core of this groundbreaking novel unfolds, it is the search itself—for meaning, for truth, for love—that offers hope for humanity's rebirth from the ashes.