Consider Phlebas

Two vast empires are intent upon each other's destruction. To the Idirans, it was jihad, a holy war against the communistic Culture and its sentient Minds. To the culture, the galactic war is a matter of principle; they oppose the fiercely religious Idirans who have destroyed thousands of civilizations in the name of their God.

The Changer mercenary, Horza, fights for the Idirans, who, despite their faults, favor biological life no matter how shortsighted or fallible it may be. He fears that soon the Minds, who crave efficiency, will realize just how wasteful humans are. Then all human life will be at the mercy of its own creation.

In this galactic war of staggering scale and ferocity, waged with a numbing ruthlessness and awesomely destructive weapons, whole habitats, moons, and planets are turned to dust and billions die. Few single entities could affect the outcome of this mighty war, but one desperate, fugitive Mind just might try.

Horza's task is to retrieve the Mind which has hidden itself deep within a fabled labyrinth on Schar's world, forbidden Planet of the Dead. No matter who or what enters his path, whether it be an enemy or an ally, Horza must get to the Mind before any one else.

Consider Phlebas teems with vivid characters and desperate adventures, and can be viewed as "space opera" at its best. But it is also, at its heart, a provocative and thoughtful examination of good and evil and the nature of truth itself. With his first science fiction novel, Iain M. Banks establishes himself as a master of the genre.