I believe there are two kinds of Iain Banks readers: those who are in it for the plot, and those who are looking for spectacle. Banks does both tremendously well, but hardly ever in the same book, which means that invariably reviews are split between people who thought his most recent novel was amazing, or merely very good.
I tend towards plot, myself. I think Banks is at his best when he keeps the scale small, and finds ways to twist and undermine his setting of high-tech, post-scarcity, socialist space dwellers, the Culture. Nobody does huge, mind-boggling scenes like him, but at those galaxy-spanning scales (and when starring the near-omniscient AIs that run the Culture) it's hard to feel like there's much at stake. My favorites, like Matter or Player of Games, combine the large and the small convincingly, hanging the outcome of huge events on the shoulders of fallible, comprehensible characters.
But for his last two books, Banks has tended more towards the huge-explosions-in-strange-places side of things. 2010's Surface Detail spun up a war in virtual Hells that spilled into reality, and now (with The Hydrogen Sonata), he's taken a look at a civilization trying to reach closure, even while long-kept secrets keep pushing up into the light.
I re-read Surface Detail this week, and I like it a bit more than I did the first time around. I still think it suffers from a lack of agency surrounding too many of its characters, who end up simply as pawns being ferried around to each major plot point, but I'll admit that those characters are charming, and the idea of the Hells--virtual worlds set up to punish people even after religion is technically obsolete--is thornier than it first appears.
The Hydrogen Sonata has a lot of the same issues: the events of its plot, while fascinating, are ultimately of dubious importance, and it's not entirely clear if any of the characters actually have real influence on anything that happens. But to its credit, the events of THS are so diverting, you almost don't care. This is Iain Banks doing spectacle at a level he hasn't really tried since Excession, and to a surpising degree it works. It's widescreen science fiction, and he's clearly having fun writing it.
The book opens as the Gzilt, one of the original co-founders (but not members) of the Culture, have decided to leave the material plane and "sublime" to a higher order of existence. Just as they're counting down, however, representatives of another sublimed civilization contact a Gzilt ship, hinting that they may have planted the seeds of Gzilt religion eons ago (and thus prevented them from joining the Culture when they had the chance). This sets off turmoil in the local government, and a gang of Culture ships recruits one former Gzilt military officer, named Vyr Cossont, to hunt down the oldest living survivor of the civilization's founding for a first-hand account of events.
There's not much actual mystery to be had here--Banks telegraphs how things are going to end up pretty quickly. But the fun is in the oversized set pieces being tossed around one after another, from the "Girdlecity" (a giant, elevated metropolis wrapped all the way around a planet's equator) to the hapless group of insects who conduct bee-like dances with their spacecraft while waiting to scavenge on the remains of the sublimed worlds. There's a Last Party being thrown by one rich Gzilt before the subliming that continually tops itself in extravagance. I was also tickled by Cossont's quest to play the titular composition on an instrument called the "Antagonistic Undecagonstring," which means she ends up lugging a bulky and inconvenient music case around the galaxy despite herself (as a bassist, I sympathize).
But while it's enjoyable enough, playing with these toys that Banks assembles, it's hard to shake the feeling that it's all a bit lightweight. The Culture has been set up in these books as tremendously powerful, almost omnipotent--it's run, if that could be said of decentralized anarchosocialists, by AI Minds at the helm of massive, powerful starships, far outclassing any of the other civilizations in the book. When there's a question of how events will turn out, it often reduces to "can ship X reach destination Y in an amount of time defined by the author?" which is not very dramatically satisfying. Like Excession, my least favorite Culture book, much of The Hydrogen Sonata takes place in catty infodumps between the Minds--these can be funny, but they can also read like you've wandered into someone else's e-mail thread by mistake.
Still, for people who are die-hard Culture fans like me, we'll take what we can get--even if I'd rather see more plot and less spectacle. Books like The Hydrogen Sonata flesh out a rich, funny, dark universe that Banks has been building for 25 (!) years now. It's good to visit, if only to point and enjoy the sights.
Surface Detail is not the worst Culture novel that Iain Banks has written--that dubious honor is reserved for Excession, which meandered through an underwhelming tour of AI politics--but it's pretty close, and for many of the same reasons. I suspect it's a problem of scale: Banks writes fantastic micro-level scheming in both his science fiction and "literary" books, but he seems to lose the thread when he tries to translate that into galactic-level politics, especially for a civilization as ridiculously over-powered as the Culture. As a result, both Excession and this most recent book suffer from a chronic lack of action, and the characters aren't given enough urgency to make up the difference.
But at least this time it's better assembled, without Excession's random plotting and character introductions. Surface Detail's A-plot concerns an indentured slave named Lededje, who's killed by her owner during an escape attempt only to wake up again aboard a Culture ship light-years away. Understandably, Lededje wants revenge--something which, for obvious reasons, her rescuers frown upon. It's a nice way of introducing another shade of grey to the Culture's supposedly-benevolent interference in other civilizations: because Lededje's killer is powerful and wealthy within his society, the Culture won't help bring him to justice, because that would cause an unpredictable shakeup of the planetary order. At the very least they need a good excuse, even if they have to make one themselves--hence the scheming, courtesy of the famed Special Circumstances department.
Banks wraps Lededje's journey with a secondary, loosely-connected plotline regarding virtual Hells: the dark side of the Singularity's "nerd rapture," they're the result of mind-state digitization technology in the hands of religious zealots. Of course, not everyone is thrilled with the idea of VR programs dedicated to eternal torment. The pro- and anti-Hell sides decide to contest their fate by holding a virtual war (the Culture is anti-Hell, of course, but abstains from the conflict for some reason). So on one hand, the book follows a soldier named Vatueil, who's fighting (he thinks) for the anti-Hell side. On the other, it watches a journalist who became trapped in one of the Hells during an undercover investigation, and ends up exploring more of their nature than she expected.
These virtual segments give Banks a place to stretch out and indulge himself: his "war over Hell" takes place in simulated scenarios ranging from creatures living the core of a gas giant to Bolo-like sentient tanks. Likewise, his Hell is a nasty piece of gothic engineering, all torture and despair. Whenever he dips into virtuality, it's always a surprise. Unfortunately, it's also too vaguely described to get an idea of the stakes or what victory means in any given scenario, and it tends to kill the novel's momentum.
So that's the general idea of Surface Detail: 600+ pages of people struggling along in increasingly clever but implausible virtual environments, and Lededje slowly making her way back to her home planet for an all-too-short vengeance. It's a funny book in parts, an imaginative book in others, but not an eventful (or ultimately, satisfying) book. And in a setting as generous as the Culture, that's a tremendous shame.
Maybe it's impossible to do real societal intrigue and plotting in a Culture book. Previous books treated the highest levels of Special Circumstances almost as distant and meddlesome gods: the inscrutable missions assigned in Use of Weapons, devastating near-genocide in Look to Windward, and (most brilliantly) the manipulative, nested strategems in Player of Games. Attempting to give readers too much insight into the Minds running the Culture seems to either undercut the omniscience Banks grants them, or it leaves the main characters entirely powerless, or both. There needs to be a delicate balance between deus and machina--in Surface Detail, he unfortunately doesn't have the mix quite right.