Written at a time when the Fear of the Bomb was at full steam, the Hugo-winning A Canticle for Leibowitz stands head and shoulders above virtually every other post-apocalypse SF novel of its day, and it may be the most important SF novel ever written. It beggars the imagination to think that this was Miller's only novel; though in 1997, the year after Miller's death, a sequel titled Saint Leibowitz and the Wild Horse Woman was finished out by Terry Bisson and released. Contemplative, elegiac, and gut-wrenching in its best moments, the story allows Miller to view the human race through a glass darkly. Will our species ever learn from its mistakes and not repeat them? Miller hopes so, though he doesn't exactly appear to think so. This book is a lament for humanity.
The story spans nearly 1500 years of future history, and details the fall, rise, and fall of human civilization as seen through the eyes of a cloister of monks holed up in an abbey in Utah. We learn of the distant past — essentially our time now — in which the world was laid waste in the Flame Deluge. Subsequent anti-science hysteria by the immediate survivors of the war resulted in the destruction of almost all antebellum scientific knowledge. And yet, the monks — who revere a martyred scientist named Leibowitz — have made it their business to recover and preserve as much of the ancient knowledge as possible. Hiding the stash away inside the abbey, scribes protect, study, and meticulously copy what little texts from before the war remain. There is little fear in seeing the mistakes of yesteryear repeated, as the texts — referred to as "the Memorabilia" — never leave their cellars and few people in the world outside the abbey and its mother church are even literate.
But change is in the air. When a young novice named Francis encounters a bedraggled pilgrim — a literal incarnation of the Wandering Jew — he discovers a previously unearthed fallout shelter, which contains writings and papers that appear to be in Leibowitz's hand. At first Francis and his claims are all but condemned as blasphemous, but when other ecclesiastical officials visit the abbey and examine the material found in the shelter, Francis soon finds himself transcribing Leibowitz's most intriguing artifact, an old blueprint for a gizmo whose original function remains shrouded in mystery. When the church in New Rome finally agrees to canonize Leibowitz, Francis's work and discoveries start to gain a little respect.
The second and third sections of the novel detail humanity's slow recovery of the knowledge of the past, eventually culminating in a world that has reestablished most of the technology long thought lost — automobiles, television, even spaceflight. And it is, once again, a world teetering on the brink of its own destruction.
Considering how, today, religion has more often than not cast itself in the role of science's perennial adversary (the whole idiotic "intelligent design" movement is an exemplar), it's easy to forget that if you go back in time a few thousand years, all the way back to Mesopotamia, the earliest science was done by the various priesthoods who also happened to be their civilization's ruling authority. It wasn't really until those damn nuisances in the West — Copernicus, Galileo, Bruno, and more — started making findings that contradicted the church's received dogmas that science and religion developed their adversarial relationship. Miller here has introduced an intriguing hybrid of medieval and earlier religious traditions. His church is entirely Catholic, with all of its schisms and politics, but the Leibowitzian monks dedicate their entire lives to the scientific method (though not, of course, abandoning their religious faith).
Most novels — SF or otherwise — that feature religion as a driving theme are usually written by true believers who just want to preach to the choir and, with luck, win over a few lost souls into the bargain. It's proselytizing in prose. A Canticle for Leibowitz is not a religious story in that sense at all. But it is about religion, and the role religion plays in society, as well as the extent to which science and religion can possibly get along. (I don't think they can, but this isn't my novel.) In the hands of a less skilled writer — let alone a writer with a strident ideology to protect — it would have been all too easy to cast this story with one dimensional cliches. You could have had all the monks be unimpeachably noble and godly men, while every scientist was an amoral villain, or you could have had the monks be hardheaded bigots and superstitious thugs while the scientists were valiant heroes just itching to advance humanity at the drop of a hat if only those annoying prats with the crucifixes and rosaries would get the hell out of the way.
Miller, a perceptive storyteller, avoids this easy pitfall. His monks are often tortured by what they know of the past, how they see civilization unfolding around them, and by the sheer futility of the task of trying to fix everything that needs fixing. This is not a traditional story with good guys and bad guys. Every human being possesses a bit of both, and the effort to bring the good to the fore while keeping the bad neatly tucked out of the way is at the core of why we are so often in conflict.
One dazzling scene near the end amply demonstrates Miller's fairness towards his characters and their flaws, as well his skill at drama. The abbot and a doctor find themselves at loggerheads over the issue of euthanizing a woman and her child doomed by extensive radiation sickness. While I think most readers will come down on the side of the doctor, both men are depicted as being profoundly sincere in their polarized views. Both men treasure life. The abbot's position is that to deprive anyone of life for any reason, including agonizing nonstop pain, is de facto wrong, while the doctor sees mercy in allowing someone a quietus from terminal disease. The scene is powerful without having to indulge in easy emotional button-mashing. It shows us two men whose ethics aren't that removed from one another's, but whose approaches to a crisis are profoundly different. And each man argues well for his position. The lazy approach that so many other writers might have taken, dressing each man in either a black or white hat depending on one's own prejudices, is never even considered.
It's true that, thematically, A Canticle for Leibowitz could be summed up in a handful of catchy taglines. "Those who do not remember the past are doomed to repeat it." "With great power comes great responsibility." That sort of thing. But overall the idea is that knowledge is the most precious thing we have. Miller avoids being just another didactic "message" writer by couching his themes in just plain great fiction. Though split into three sections, each set about 600 years apart, the novel is never less than completely absorbing, and there are scenes of both comedy and gut-wrenching compassion. There are a few scarifyingly prescient moments, too, if you catch them. Miller at one point alludes to an organization called the Christian Coalition, almost 40 years before there was a real one! There are also passages that recall, sadly, an all-too-common political baseball bat being wielded right now by so many folks in this country; to wit, the idea that questioning or criticizing the actions of your government in any way is tantamount to treason and giving aid to the enemy. That people still have these asinine attitudes today shows how far we still have to go before we can reasonably be assured that our own future won't look like the one in this sobering, unforgettable novel.