For me, a satisfying conclusion to the trilogy, continuing to push the themes of race, gender, nuclear armageddon, sex and biology. The alien-human hybrid Jodahs is the narrator. It - for that is its pronoun - is another Christ figure, like Akin in the previous novel. But this time the name suggests Judas, and there is frequently a suggestion that a putative mediator could turn out to be a betrayer.

One thing I like about Butler is how she goes to extremes. In this case the most sexually desirable creatures left on planet earth are a community of nuclear mutants afflicted with debilitating degenerative conditions and horrible skin diseases. Bow-chicka-wow-wow!

In her other novels (e.g. the Patternist series) she portrays the worst traits of human debauchery and murder, just to make it hard to pick a side - hegemonising aliens or violent human psycho-killers. Here I found I had sympathy for her protagonist Jodahs, but at the same time the ooloi are an alien species with a special gland that excretes the ultimate date-rape drug. One whiff and you can't help falling in love with that tentacled freak from space. Consent and free will, it seems, are more complicated in the post-nuclear alien contact phase of humanity.

But then, Jodahs doesn't have any choice in the matter either, it has to find human mates or descend into a suicidal metamorphosis where it devolves into a mindless slug and finally dissolves itself in the post-nuclear swamp.

Much as this is a compelling story with some appealing concepts, Butler's futures are not aspirational.