This story is parallel to "Oryx and Crake" (http://www.goodreads.com/review/show/23324423), and has several characters in common, though the writing style and overall format is quite different. Having read both, I can't decide whether it is better to read them in publication order (O&C first) or not, but it's certainly good to read them in quick succession. As with O&C, it is about the characters; many aspects are only ever partially explained, part way through, leaving the reader suitably disoriented in this distopian world.
It tells of the run up to and aftermath of "the waterless flood" in the near future: a man-made plague, which has wiped out most of the population and damaged the climate. It focus on an eco-religious community (cult?) called God's Gardeners. They foresee the flood and prepare for it, and in the interim, they are self-sufficient vegetarians, who scrounge scraps to reuse and recycle, and avoid the corrupt CorpSeCorp (police) and corporations that run society: "They view us as twisted fanatics who combine food extremism with bad fashion sense and a puritanical attitude to shopping. But we own nothing they want."
Every third or fourth chapter is a sermon by Adam One, followed by the words of a hymn. The result is a curious combination of anti-capitalist eco treatise and satire, Biblical-style liturgy, and end-of-the-world fight for survival, with dashes of bathetic humour - but overall, Atwood makes it work.
The story focuses on resilient, loyal female characters: Toby, who escapes various abuses to join the Gardeners as an adult, and Ren, who is taken from the safe luxury of a corporate compound when her mother runs away with a gardener. The male characters are flat and in the background (even the leader, Adam One) or bad (Blanco), though somehow it doesn't feel like a feminist rant. Ren's sections are mostly recounted in the first person and Toby's in the first.
Although it jumps around timewise, the first part of the book has plenty of positive aspects (and some vague angst), whereas the later sections are unrelenting accounts of the lengths (and depths) people will go to in order to survive, even when they are unsure if it is worth it: "This thing I'm doing can hardly be called living, Instead I'm lying dormant, like a bacterium in a glacier. Getting time over with."
The eco theme is obvious, but actually, the exploration of cult mentality is more fundamental and interesting, and it raises far more questions than it answers, exploring the many reasons why people join - and remain in - cults: no where/one else, fear, idealism, escape, drifting, actual belief, loneliness, wanting to be taken care of and not have to make decisions, even just by accident. And of course, power tends to corrupt. The senior Gardeners (Adams and Eves) break and adjust their own rules. For example, they have (and use) a laptop ("It's like the Vatican porn collection... safe in our hands") and they make surprisingly pragmatic changes to their belief system, looking for reasons to justify them afterwards.
It avoids being depressing by having plenty of gentle humour and irony: a genetically-modified caterpillar has a cute babyish face, making it hard to kill, and at the end of an earnest sermon, Adam One ends "I'm glad we have all remembered our sunhats". For all their ideals, the Gardeners are eminently practical. Another comment of Adam One's is painfully ironic, "'Nothing bad will be done to you.' But since Adam One thought even the most terrible things happened for ultimately excellent though unfathomable reasons, X didn't find this reassuring." Atwood even points out in the acknowledgement that readers are free to use the hymns for "amateur devotional or environmental purposes"! It is also full of punning portmanteaus: the exfernal world, rakunk (rat-skunk), SeksMart, AnooYoo Spa, garboil (oil from garbage), liobamb (lion-lamb).
The ending is very abrupt (very slight just a different view of the final scene of O&C) and after more than 500 pages, I was still unsure whether Atwood wants me to agree with the Gardeners or to laugh at them. Although I tend to like ambiguous endings, I was taken aback and slightly disappointed. However, a few hours later, when I'd really thought about it, I think it was the right way to end.
I think it would have benefited from a little pruning - the level of detail about Gardener lifestyle and some of Adam One's sermons, but that's a small quibble about an excellent and original novel.
"Nature full strength is more than we can take... It is a potent hallucinogen, a soporific for the untrained Soul. We're no longer at home in it. We need to dilute it... And God is the same. Too much God and you overdose. God needs to be filtered."
Less reverently, and from a non-Gardener: "As soon as you say 'I'll be dead,' you've said the word I, so you're still alive inside the sentence. And that's how people got the idea of the immortality of the soul - it was a consequence of grammar. And so was God, because as soon as there's a past tense, there has to be a past before the past, and you keep going back in time until you get to 'I don't know', and that's what God is."