Image via Wikipediaut their territory, stretch their arms and sign multi-book deals to keep themselves in pizza and jellybeans. I know I do.
I've long been jealous of Charles Stross' use of abstruse mathematics as a way through to other dimensions where man can truck with named and nameless horrors. I really enjoyed The Laundry series of books that update the Mythos (so peeved by that use of Lake Vostok) and add in Turing's well-known paper "Phase Conjugate Grammars for Extra-dimensional Summoning" to give it a modern twist. How I'd love to have such an idea for myself. Oh, mustn't forget that it all first appeared in A Colder War - though that is much bleaker than the subsequent books.
It's not entirely his own though because, even though he did not perhaps realise it, HP Lovecraft made use of such an idea in Dreams in the Witch House. Keziah Mason escapes jail by using mathematics to reach other dimensions enabling her to reach the modern world and kill again. Fritz Leiber pointed out that this was one of the first uses of hyperspace. A term coined by John W. Campbell and that first arose as a concept in the 19th century.
Mention of not the "spaces we know, but between them" crops up in other stories too - including one of my faves The Dunwich Horror. The whippoorwills! Here's something I didn't know - it was turned into a movie - twice. Looks like neither was any good. Though the 1970s one has Dean Stockwell and Sandra Dee in it. Dean Stockwell pops up in the second too but as the good guy rather than one of the Whateleys. The Wikipedia page lists lots of times it has been turned into media of one sort or another.
I first read that story in a book of classic ghost stories. Lots of MR James, HH Munro et al - all very staid and Edwardian. In that context HP Lovecraft's story stuck out a mile. To this day I'm still struggling to picture what the Horror looked like but can remember parts of it clearly. How old must I have been when I read that? 12? 13? No wonder I ended up playing so much Call of Cthulhu. Shapeless congerie of protoplasmic bubbles anyone?