The novel is set in the far future, with humans on many worlds. Some have god-like powers, or perhaps are gods - the names and aspects of various Egyptian Gods are used. Elements of horror and technology are mixed, and it has points in common with Cyberpunk.
Creatures of Light and Darkness was originally conceived and written as nothing more than a writing exercise in perspective by Roger Zelazny, yet when published turned into one of Zelazny's more popular books.
Unlike other books by Zelazny, such as Lord of Light or the The Chronicles of Amber series, this novel is more poetic in style, and contains less straightforward action. However, like other novels, Zelazny incorporates ancient myth, in this case from Egyptian and some Greek myth, and weaves ultra-futuristic technology with fantasy elements.