The world following a nuclear holocaust will have few survivors and they will be frightened, confused, sick, and angry. In A Canticle for Liebowitz, published in 1959 at the height of Cold War anxiety, survivor's anger takes the form of distrust of and disdain for all things of the intellect. After the war (six hundred years before the book opens) and the resulting chaos and destruction it wrought, the masses set their sights first on the governments and rulers who waged the war, and then on those who enabled it with their theories and inventions--the scientists, teachers, writers, intellectuals. This time is called the Simplification, and its bloodletting includes seeking out and destroying machines and books and those who created and understood them. Bloodthirsty simpletons! the intellectuals call the masses, and they embrace the name; eventually, simpleton will become the accepted term for any citizen.
The book is divided into three sections, all of which center on the Abbey of the Order of Albertus Magnus, formed by Isaac Edward Liebowitz (a scientist in the world that came before) in the third decade after the war. Fiat Homo--Let There Be Man--is set six hundred years after what has become known as the Flame Deluge, during a time of gathering and protecting of knowledge by a very few. The monks who follow the blessed Liebowitz are the lone protectors of intellect in the wasteland of isolated city states the world has become. Its members are "bookleggers" (and a more wonderful term I haven't come across in I don't know how long), who seek out surviving books and smuggle them to the abbey where they're buried in kegs, and "memorizers," who commit to rote memory volumes of science, history, literature, and sacred writings. The second section is Fiat Lux--Let There Be Light, and is set six hundred years after that. This period sees the first reblossoming of invention and discovery, as well as the beginning of war among the city states. Finally, Fiat Voluntas Tua--Let Thy Will Be Done, has the world coming full cycle, eighteen hundred years after the holocaust that toppled the last great civilization.
A Canticle for Liebowitz is grim and extraordinarily pessimistic, but somehow still hopeful. It is peopled with rich, often funny, characters: Brother Francis, the young novitiate in Fiat Homo who, while in the desert on a Lenten fast, discovers, in a buried fallout shelter, a cache of documents belonging to the blessed Liebowitz; the Pilgrim, a mysterious, cackling old man who appears at key points in each of the book's three sections; and the Poet, a professional fool who spends some time in the abbey. Ultimately, although Miller's vision is one of history repeating itself, endlessly, as civilization after civilization replicates the growth, achievements, and pitfalls of the ones that came before, still, he sees the spark of optimism, goodness, and intelligence in the race that keeps us striving and, consequently, alive.