It's split into three parts. Fiat Homo (Let There Be Mankind) follows Brother Francis, a young novice in the Albertian Order of Leibowitz in the 26th century. This is 600 years after a nuclear war. The human race very nearly died out and many are born with birth defects. In a backlash against technology and learning, the Simplification destroyed books and killed scientists, leading the world into a new dark age.

The monks preserve Memorabilia, relics of Leibowitz who they are trying to get canonized. As a reader you soon realise what these relics are, but the monks have no idea of their meaning. It shows the importance of preserving knowledge but also the context.

Brother Francis is a bit of a nervous, naive chap. He discovers a fallout shelter in the desert, in which he believes he's found a relic, a drawing made by Leibowitz himself. The Abbot isn't too keen on miracles right now, they'll only interfere with their petition to New Rome for Leibowitz to be made a saint. It pokes fun at the Catholic church but also ponders how religion and science co-exist. It's actually quite amusing in places and some of the characters wouldn't feel out of place in Discworld.

Fiat Lux (Let There Be Light) is set in 3174, where scholars are starting to take an interest in recreating the technology of the past. At the abbey, one monk has used the teachings of Leibowitz to generate electricity. Whilst some view this with suspicion, others see the potential.

Fiat Voluntas Tua (Let Thy Will Be Done) takes a much sadder turn. The year is 3781 and mankind has not learned from their mistakes. Perhaps the point is that as history was destroyed and forgotten, no one remembered how bad it was last time. It's very much a Cold War era book.

In what I imagine was quite shocking at the time it was published, it talks about the right to die. I found it quite upsetting how the Abbott resisted the state sanctioned suicide for those suffering with no hope of recovery. A mother just wants her daughter to not be in pain and the Abbott is forceful about how God wants her to suffer and they must carry on to avoid hell.

A satire that starts out with humour definitely ended on a much more sombre note. I'm glad I read it and I can see its influence on other, post-apocalyptic, works.