I think it was one of the first books to investigate this, but the theme has been used many times since. I will read them at every opportunity, and borrow them when I can, but even then you have to find the series which are a cut above the rest. The Sandman series almost need no introduction. Morpheus is the Lord of Dream. Not quite a God, but Morpheus has a strange disdain for interfering in his domain.
Nightmares come and go, but that is the natural way of things.
If so, then they are long since dead. This story is yet another gore-fest of violence and mental illness. Don't pick up a single Sandman comic in isolation. You need the padding of a few sequential issues, or else the fantasy world will not make any sense whatsoever. Other Books By Gene Wolfe. .