Declaration of interest: I was given a copy of this book by the publisher.
This is a big book with big themes - environmental collapse, colonialism, the corruption of noble ideals, totalitarianism. Most of all, perhaps, it's about growing up.
As the story opens, Astra is a young girl living a happy life in a rural commune in a remote corner of Is-Land. Is-Land is a state established following the Dark Times. It is a place devoted to Gaia, the Goddess of the earth. Is-landers are extreme vegans, living off the produce of the land, seeking to harm no animal or plant. Yet they have a sophisticated society, employing not only tablet computers (where and how are they made?) but advanced genetic engineering ("Code") which furnishes them with drought and radiation-resistant plants.
It also, however, allows for darker manipulation, and the driving force of the story is the inoculation of Astra's yeargroup with the "Security Serum". This will make them tougher and healthier - but also more trusting and controllable, less prone to emotions like fear and anger. It will turn them into the "Security Generation" or SocGen, natural cannon-fodder for Is-Land's anticipated invasion by "non-Landers", malign intruders who want to tear down all that the Gaians have built.
As the story develops, moving into its central section, we hear more about these non-Landers, though we never meet any. We do learn, however, that they have been expelled from Is-Land by force - it becomes clear that Is-Land itself is a darker place than it seems, and Astra's growing up, a lone non SocGen among her conformist peers, forces her to challenge not only her family but all that she thinks she knows about Is-Land.
It's a powerful book, with distinct echoes of other dystopias and stories of revolution-gone-wrong: the sinister, controlling but never explained Thought Police IMBOD is everywhere, and the rewritten words of the Is-Land anthem in the opening section reminded me of Animal Farm. There are nodes to Brave New World, too, in the frank attitude to sex - indeed this is a startlingly explicit (though never smutty!) book, and that enables Foyle to address some issues and show Is-Land at its best - for example in its tolerance of a spectrum of sexuality. But there are darker aspects to this, as well, and we're left in no doubt about the power that IMBOD wields in a particularly gruesome climax to the Blood and Seed Ceremony.
There is, as I said before, a lot in this book. Some might find its opening rather slow and be discouraged - Foyle has a lot of detail to establish, and she lets her characters grow in the imagination, and the plot flow from them - but it would be shame to give up on this book, as the details, the relationships and the characters are crucial for the events that follow later (in this volume and, I'm sure, in sequels).
It's a chewy read in another way - one of those books that needs to be taken slowly and carefully, letting the descriptions and the atmosphere sink in. A book that repays careful read many times over.
Highly recommended.