"Matter" is another epic space opera in the "Culture" series. I've enjoyed (and reviewed) "Consider Phlebas", "Look to Windward", "Use of Weapons", "Player of Games", "Against a Dark Background", "Inversions" and "Excession", and "Matter" is a fine way to end the run.
Banks is a master of bringing a fresh perspective to what could easily be repetitive and derivative material. Often he uses contrasts to keep the perspective fresh. In "Inversions" and "Consider Phlebas", we see The Culture contrasted with its enemies. In most Culture novels, we see The Culture contrasted with the more primitive societies it tries to nudge towards its higher ideals. In "Excession", we see The Culture contrasted with both an artifact from advanced society and its enemies.
In "Matter", we get the best of these contrasts and new perspectives to boot. We follow one of The Culture's newest recruits as she returns to her homeworld during a time of crisis. We also follow her brother as he works to escape the political turmoil of his homeworld and encounters his "Cultured" sister. As if that weren't enough, we also see how citizens (human and machine) of The Culture deal with technologies beyond their own when cut off from the full resources of their own society.
Banks continues to amaze with the imagination he brings to each book. The Culture series is astonishing in its scope, and in between all the fantastic ideas and characters are enough amusing and well-crafted phrases to make it nearly exhausting. I'll have to get plenty of rest before the new Culture novel is released next year. If you haven't already done so, take advantage of the deals and reprints leading up to the new release and enjoy the whole series.