Iain M. Banks died earlier this year at a sadly young age, after establishing a reputation as one of the most literary SF writers of his generation. He wrote non-genre fiction (as Iain Banks) as well as SF. Most of his SF novels are set in the Culture, a galactic humanoid utopia in which almost inconceivably advanced technology provides everything that is needed, immensely capable Artificial Intelligences sort out the mundane business of running civilisation (the most powerful, known as Minds, usually being established in vast spacecraft or space habitats with quirky names), and citizens are mostly free to do whatever they like – live forever, change gender or even species, travel the galaxy. There are various alien civilisations in close contact with the Culture and a lot of others that are not, plus human planetary settlements that don't enjoy the same benefits. Relationships with such peripheral groups are handled by an organisation called Contact, and they apply less diplomatic means when required by means of Special Circumstances, whose agents are kind of blend of James Bond and Jason Bourne with comprehensive bio-electronic enhancements.
Matter is mainly set in one of the peripheral human civilisations outside the Culture, which has occupied part of the Shellworld called Sursamen. Shellworlds are artificial constructs made by an earlier and long-gone civilisation aeons ago. They are habitats the size of large planets and are made up of fourteen concentric hollow spheres, each one providing a land surface comparable with a conventional planet, held apart by a million vast columns through which travel between the spheres is possible, and lit and warmed by thermonuclear "suns" tracking across the 1,400 kilometre-high ceilings. The Shellworld is one of the stars of the novel just as the Ringworld is of Niven's eponymous novel, its curiosities being described in detail including a huge waterfall which is cutting rapidly back through the soft earth, revealing the remains of a forgotten city of great age and sophistication.
Different species occupy different spheres of the Shellworld, but the humanoid civilisation on the eighth and ninth layers is at a kind of feudal steampunk level, still engaged in fighting wars of conquest. The main focus is on the nation called the Sarl that occupies the eighth layer and is engaged in battle with the Deldeyn of the ninth. The Sarl are mentored by an alien species, the Oct, which have developed an inexplicable interest in the forgotten city, especially in the latest excavations which have uncovered something rather strange. There is treachery and tragedy afoot among the Sarl, which draws home a princess of the ruling family, Djan Seriy Anaplian, recruited as a child by Contact and now a Special Circumstances agent. The story switches between Anaplian and two of her brothers until they are finally drawn together.
As is typical of this author, Matter is a long and complex novel in which the creation of atmosphere and background takes precedence over the action for most of its length. It is full of rich descriptions of places, people and situations, flavoured with Banks' usual wry humour. This slow start means that dramatic tension suffers, although in the latter part of the novel the pace rapidly accelerates towards the explosive conclusion. Until then, this story is not a gripping page-turner but if you like Banks' style, you won't want to miss it. In particular, the Shellworld is an invention that is likely to stay in the mind for a long time.