The explosions at the end of Iain M. Banks' Matter are still ringing in my ears. He's getting really good at constructing very clever things. Scratch that, he has been really good for quite some time at telling clever stories, that are much easier to deal with at face value, than to properly think about what's inside. I'm sure it's deliberate.
On the surface, it's a typical Culture space western. The high plains drifter is played by a young woman, of course an Agent of Special Circumstances. And of course, accompanied by a lethal bundle of technology and irony in the shape of the hovering offensive drone. Highly dangerous, and yet supremely moral, they can stop an army of heavily armed knights just by thinking about it (and harassing the column with weapons invisible to pre-technological eyes). They pluck some victims of primitive war from destruction, and shelter them aboard their god-like ships. It's primarily these two who we follow, as they crash around, and with their clever tools and tech, save at least one world from horrid alien interference.
However, it's the worlds in question that deserve a closer look. The wider world of the life-strewn galaxy is painted in, like a Victorian genre picture of a day at the races. All types are there, and some of them are those that you might actually want to meet. But with most of them, you are glad to be back in your armchair on Earth. As with other Culture novels, Banks is at the same time completely cynical (all species are bastards, and the bigger species are sometimes the biggest bastards) and also brightly optimistic (generally speaking, trillions upon trillions of members the want-for-nothing super-species just loll around having delightful egalitarian funny naked sexy lives in their sentient super-homes, causing absolutely no trouble at all).
Another world full of humans is depicted. One tribal faction fights another, through sweat, mud, blood and pain, for supremacy of their part of their backward planet. Most of them are firmly trapped in this bubble of pre-development, and while they might know that there are higher beings, such as the Culture people, out there above them, they also know that they are powerless to reach through the bubble. As we read of their wars, we know that their factionalism is pointless (they are the same species) and their religion is void (their god is a squatter who couldn't care less about them). However, although there is hurt and destruction in their slice of the world, there is, there is at the same time love, hope and honour.
The planet, it is realised, is a Shellworld, a Nautilus-like construction, yes a machine!, of concentric chambers. Dozens of species dwell in the spaces, some walking on earthy sub-surfaces underneath the glow of rolling mechanical sunlets (nuclear? stranger physics?), others flopping in enclosed oceans or floating in endless clouds, others enjoying the vacuum of their compartments. Huge struts or arteries, called Towers, let the action slip, via hermetic doors millions of years old, from one sub-world to another. This in the true spectacle of the book, and the other characters and species dance around it and through it.
The humans are effectively pets of the local alien overlords (there are several to choose from), who happen to be floating, slightly smelly, multilegged and hilariously ungrammatical. The turf war is fought out with carbines, swords and lances, and the occasional mounted creature. The faction having recently discovered steam power (probably informed by the spindly wotists or perhaps the stinky blobules) gains the upper hand, and forges an empire. However, there is bittereness. Not only do thousands die in the wars of occupation, but the rightful king is sneakily deposed by an obviously evil schemer. Our heroes are royal splinters in this struggle (and the SC agent is a sister to them). Meanwhile, the world's systems (naturally, it's got an infinity of software and embedded mechanisms) are being interfered with by who-knows-who, and there are these strange movements of starships. It's a little like a quest to restore Narnia in a far-off galaxy. SC drones play the fauns and forest creatures, and a sentient ship plays an Aslan.
So Hoorah when the protagonists not only restore order, but also intervene to stop the whole concentric world from destruction. And then Aahh, when orphans are all given hearths and homes beneath the peaceful rolling anti-gravity ceiling blobs.
But there's doubt, just as Banks intended I'm sure. Just who controlled who in the chain of rebellion and chaos? Did we really just sympathise with the suicide bomber in service of the primitive monarchy? What was the true function of the mechanical world? Not for living in, that's obvious, and purpose of the colossal mechanisms at its centre remains obscure. Why did the eons-frozen egg/bomb/demon so want to destroy it? Was it lying when it said the Shellworlds were a timebomb, an environmental threat of their own? Perhaps the happy-ending pulled from tragedy is really a disguise for a further sinking into a sea of doom.
Perhaps, as for the humans trapped down in level 8, there is much more above and below than we can reliably process. And if we can do anything about it then fine, but if not, then we may as well enjoy ourselves.