When Imre Bergamasc wakes up on a Jinc ship on the outer edges of the galaxy, he has lost his memory, but remembers enough to realise that he should not be in a female body.

The Jinc tell Imre that they've reconstructed him from an artefact they found: an iron drum inscribed with grooves of coded information – essentially a back-up copy of him. Ominously, someone had used nuclear weapons in an attempt to destroy the drum; as the Jinc warn him, the copy of his old self is not perfect.

It is the 879th millennium AD, and human life has changed almost unrecognisably. People can be copied perfectly; anyone who chooses can have many separate 'selves' who can go their separate ways; if they meet up, they can exchange or merge their memories.

People can also spend time as pure data in hard-storage, and later can be reanimated. With sufficient backup, people can, effectively, be immortal. At the time the story takes place, a version of Imre has been around for more than 500 millennia.

As the reanimated Imre struggles to regain his memories and his history, he encounters colleagues from the Corps, a small group of ruthless mercenaries who have fought as a tight-knit team over hundreds of millennia. The memories that come back to Imre are dangerously patchy, and his eccentric, violent colleagues remember much that he doesn't about the actions of his past selves.

Imre seems to have no memory of the galactic disaster that has destroyed the civilisation of the Continuum, now collapsed into chaos. He gradually comes to fear that some version of himself was involved in the destruction.

Imre is often disturbed to hear of the things that his past self, or selves, did: the new copy that the Jinc have made seems to be a rather nicer person than the old Imre. More identity problems are raised as Imre's colleagues encounter different versions of themselves, not all of them friendly. But while Saturn Returns explores the concept of personal identity, it does so in the midst of a plot packed full of tense, violent action.

Adelaide-based author Sean Williams is one of Australia's most prolific and successful writers of fantasy and science fiction. Saturn Returns, the first of the Astropolis series, is his first solo space opera novel, but he has written more than 20 books, including three acclaimed space opera series co-written with fellow Australian Shane Dix.

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