Confluence

I read this several years ago and was blown away by the concept of an artificially created world, long abandoned by its creators, and maintained by machines some of which are understood and controlled by the world's current inhabitants. When an orphan child appears who can control the world's machines, he becomes sought after by differing sides in a protracted religious war.

The author creates a rich, believable world that is both ancient and technological, and a political structure ruled by competing departments that will ring true with anyone whose ever been within ten feet of a bureaucracy.

This edition is a trilogy book, containing all three books, Child of the River, Ancient of Days, and Shrine of Stars. I picked this up to read again and am halfway through Child of the River. I'll have more when I finish reading this.