Warning: spoilers abound.
The most compelling dystopias and post-apocalypses are so because they are believable: the ease of imagining a boot stamping on a human face forever in our world gives 1984 its power; and here, the inevitability of humanity re-annihilating itself after two millenia rebuilding from a first nuclear apocalypse rings just as true.
There is grinding mundanity in this book – centuries of it.
There is brutality and barbarism, both filling the vacuum left by the near-complete destruction of our civilisation.
There are machinations, too, drawing another apocalypse ever-nearer. These are just the same as the machinations, lusts for power, and increasing inabilities to co-exist that define our world now.
Most believably, there are innocent people trying hard to live their lives and make their own small contribution to humanity while being swept along by destructive tides they have no power to influence.
And there is a dark, subtle humour that somehow makes this bleak world bearable.
Overall, the perfect balance of unlikely elements makes A Canticle for Leibowitz maybe the most believable post-apocalypse I’ve encountered in literature. Made all the more unsettling for requiring nothing we didn’t already have in our world when Walter M. Miller Jr wrote it nearly 70 years ago.
The closer men came to perfecting for themselves a paradise, the more impatient they seemed to become with it, and with themselves as well … When the world was in darkness and wretchedness, it could believe in perfection and yearn for it … [now] this garden Earth, civilized and knowing, [is] to be torn apart again that Man might hope again in wretched darkness.