Considered in turn a Gothic novel, a psychological case study of an unreliable narrator, and an examination of totalitarian thought, the ultimately unclassifiable novel is set in a pseudo-Christian world of angels, devils, and demonic possession. It has been the subject of increasing critical attention in recent years, and has received wide acclaim for its probing quest into the nature of religious fanaticism and Calvinist predestination.

It is written in English, with Scots appearing mainly in dialogue.