I thought it was an excellent read; I would go so far as to say it is one of my favorite science fiction novels.
For those unaware, A Canticle for Leibowitz
is a 1960 science fiction novel by Walter M. Miller Jr., centering on the Albertian Order of Leibowitz, a Catholic monastic order based in the American Southwest that has dedicated itself to the preservation of knowledge in the wake of a nuclear holocaust. The novel is separated into three parts, and each part is separated by 600 years, with the novel beginning 600 years after the nuclear holocaust, or the "Flame Deluge". Thus, the events of the novel span eighteen centuries. Its themes include the relationship between church and state, humanity's tendency to repeat its own mistakes, among others. While the book as a whole can be characterized as rather melancholy, it is punctuated by many moments of dry humor, which never failed to get a chuckle out of me.
I would wholeheartedly recommend it.
Here's the summary on the back cover of my copy.
"In the Utah Desert, Brother Francis of the Albertian Order of Leibowitz has made a miraculous discovery: the relics of the martyr Isaac Leibowitz himself, including the blessed blueprint and the sacred shopping list. They may provide a bright ray of hope in a terrifying age of darkness, a time of ignorance and genetic monsters that are the unholy aftermath of the Flame Deluge. But as the spellbinding mystery at the core of this novel unfolds, it is the search itself - for meaning, for truth, for love - that offers hope to a humanity teetering on the edge of an abyss"
Oh, and I forgot to mention: the book is one of the inspirations for the Brotherhood of Steel from Fallout, which is how I first heard about the novel.