Lovecraft gets into some pretty advanced concepts in this story, such as using complex math to gain access to multi-dimensional worlds.
This story uses the same mythos as that of “The Shadow Over Innsmouth,” but actually pre-dates that story by three years.
Our narrator is named this time—Walter Gilman. (Why the same name as the alien-infested hotel in Innsmouth?)
We are in the “legend-haunted city of Arkham.” Gilman has taken a room in Witch House on purpose because he is fascinated by the history of Keziah Mason, who was on trial as a witch. She had told the judge “of lines and curves that could be made to point out directions leading through walls of space to other spaces beyond. The strange angles in Gilman’s room have a curious effect on him and lead him to become more and more obsessed with thoughts of travel to another dimension. He does succeed, but at the cost of his sanity and his health. Lovecraft has Gilman continually question his own sanity, probably because we know that insane people think that they are perfectly same; because Gilman is rational enough to question his own sanity, he is sane.
He contacts the witch and her evil little familiar, Brown Jenkin, and from there, it is a slippery slope into oblivion.
Lovecraft has his protagonist tell everyone around him about the supernatural goings-on: his fellow boarding house mates, his professors…and they all believe him and help him out as much as they can. They don’t try to have him committed. This is unheard of in more recent fiction.
Gilman has dreams that result in objective reality, such as the little gizmo that is left behind after one of his nocturnal jaunts, his house mate looks through his keyhole and sees the blinding light that his emanating from Gilman’s night time bedroom.
His descriptions of the other dimension are fascinating. “…the tiles were cut in bizarre-angled shapes which struck him as less asymmetrical than based on some earthly symmetry whose laws we could not comprehend.”
We don’t know that much about Gilman, but Lovecraft does get into his head and tells us exactly what he is feeling: the obsession along with the blinding fear. When he risks his life to avert the sacrifice of a baby by the witch and her cohorts, he proves to us that he is a worthwhile, likeable guy. He kills the witch but is also killed himself by horrible means or something (presumably Brown Jenkin) burrowing completely through him.
Lovecraft repeatedly refers to a magical book called the Necronomicon, which is completely fictional. People have tried to find it or recreate it over the years, all for naught.
I was very drawn in by this story and impressed by the advanced concepts of math having an effect on multi-dimensions. He was way ahead of his time.
Lovecraft didn’t care much for people. I read a quote of his, "... all my tales are based on the fundamental premise that common human laws and interests and emotions have no validity or significance in the vast cosmos-at-large." Despite this, in Dreams in the Witch House Lovecraft draws us into his characters with his attention to detail and by the deep perspective of his characters.