Some reviewers have complained that Banks takes too long getting the story started, but they’re missing the point. Matter can be seen as a bridge between Inversions, which takes place through two alternating, and perhaps connected, stories, one in a nation similar to those of Dark Ages Europe, and the other in a culture similar to the Islamic world of the same time, but with hints of Culture activity, and a full-blown, in-the-midst-of-it book such as Consider Phleabas or Use of Weapons.

In Matter, we’re introduced to Shellworlds, multilevelled world-sized machines built by a long-since disappeared race for some mysterious purpose. In more recent times, some members of a race of powerful aliens have taken up residence at the cores of these worlds, and various levels have been converted to provide homes for a variety of different alien species including vacuum-dwelling Starseeds and, happily for us, some human-like peoples.

And so we are introduced to the Sarl, a “human” race living on the Eighth, the eighth of fifteen habitable levels of one of the remaining Shellworlds. They had been living at a roughly medieval technology level, but have, with some hints from a Culture Special Circumstances agent achieved some significant advances in artillery, smaller firearms, and steam-powered vehicles. They are at war with the denizens of another level, and the battle takes a surprising turn, pushing two sons of the royal family in very different directions.

Meanwhile, back in the Culture, we’re introduced to their sister, who has left the Shellworld to live in the Culture and learn about them, and has spent some time in Contact before being invited to join Special Circumstances. Events on the Shellworld call her home for what are initially personal reasons, but which evolve into something much more complex and demanding as the story moves forward.

As with most of Banks’s Culture stories, we see the Culture through the eyes of outsiders. In Matter, we’re also introduced to a number of other “Optimae” - very powerful groups of aliens with their own complex desires and interests - as well as several “client” species, who also have complex and frequently conflicting desires and interests. Through Anaplian, we learn more about the Culture, how it recruits and trains its agents, and how it chooses to project its power in the universe. Her brother Ferbin and his servant cum companion Holse learn more about the race that considers them a client culture, as well as those alien Optimae who oversee those races. What they see and learn is not all good—despite, or perhaps because of, their power, the Optimae choose to meddle in the affairs of “lesser” species (as well as each other) to different degrees; they are also more than willing to exploit these groups for their entertainment value.

As the story moves on, we learn a great deal about the various races involved. Oramen, the second prince, keeps us involved with events on the Shellworld itself. As we approach the end of the book, events build rapidly to tragedy, space-opera drama and excitement, and even surprising heroism and sacrifice.

The universe within which the Culture operates is fantastically diverse, and despite the often epic sweep of Banks’s novels, we are still always left understanding only a small piece of the full history and drives of this powerful conglomeration of people and machines. Matter is a fine addition to the compendium.