A Canticle for Leibowitz opens 600 years after 20th century civilization has been destroyed by a global nuclear war, known as the "Flame Deluge." As a result of the war, there was a violent backlash against the culture of advanced knowledge and technology that had led to the development of nuclear weapons. During this backlash, called the "Simplification," anyone of learning, and eventually anyone who could even read, was likely to be killed by rampaging mobs, who proudly took on the name of "Simpletons". Illiteracy became almost universal, and books were destroyed en masse. Isaac Edward Leibowitz had been a Jewish electrical engineer working for the United States military. Surviving the war, he converted to Roman Catholicism and founded a monastic order, the "Albertian Order of Leibowitz", dedicated to preserving knowledge by hiding books, smuggling them to safety (booklegging), memorizing, and copying them. Centuries after his death, the abbey is still preserving the "Memorabilia", the collected writings that have survived the Flame Deluge and the Simplification, in the hope that they will help future generations reclaim forgotten science.

A masterful achievement that ranks with Brave New World and 1984, this mesmerizing tale of the terrible aftermath of nuclear war has captivated generations of readers since its first publication in 1959.