Not only do his writings revolve around the ancient, cosmic beings, that covet to rule over humans, they also speak of people, who serve those beings. A servitude that has been passed from old generations to new ones, wanted they it or not. Incestuous ancient families, which guard the secrets of the great old ones, waiting for the start to align so they can re-enter to our plane of existence.
Another interesting question about Lovecraft is, how much did his own personal psyche influence in his imagination of those horrors. His own racial prejudices, especially when describing those old, savage races and degenerated people who held the secrets of the old ones. Or how much his own rigid Victorian views of sexuality and sex, in general, influenced how he described the ceremonies taking place in those cults that worshipped Dagon or Cthulhu.
To me, Lovecraft is not a horror writer though. He's more of a writer about hysteria, as that is the state his narrators often seem to be in. Hysteria and madness, mixed together into a narrative that often feels more than a bit unreliable. Which also leads into question: how much of the words of the narrators Lovecraft indented to be taken as a "fact" and how much of it really is just ramblings of a madman, as that is a theme I think Lovecraft himself seems to be most interested of: how does a lunatic see the world around him and how much of his statements can be taken seriously.
So how does it all tie onto Alan Moore's Neonomicon, his yet another take on Cthulhu mythos, this time in contemporary, at least partly so, settings. Well, it ties on so, that in this world Lovecraft was a writer who knew that the eldritch horrors existed and he wrote about them as a fact, but as one member of the secret Dagon cult says, he got some things wrong.
Neonomicon isn't pure horror either. But it also isn't pure hysteria nor is it a study of madness. It is somewhere in between. While it's well written, just like you'd expect Moore's writing to be, it also is a bit underbaked. Moore presents interesting ideas, but at places, he just doesn't seem to go anywhere with them. A lot of the things that happen in the story are left in the sidetrack which is never really visited again.
The conclusion Moore gives to his story is interesting enough though. The road to it, while a bit straight forwarded and almost a bit too fast forwarded screaming a bit more meat around it, is interesting none the less.
What also is interesting is, how different Moore's heroine FBI agent Brears is of any character Lovecraft himself created. If placed into the same situation Lovecraft's own narrators would have succumbed to hysteria or madness. They would have described how the world around them would not have made any sense and they'd fainted or lost their wits, only to find themselves out of the situation where they were in.
Brears, on the other hand, later on, takes charge of the situation. Not immediately. Not before she's been badly abused by the cultists, but her mind doesn't crumble into pieces. But, as she herself states in the end, her mind might be influenced. So, when all is said and done, how much can we really trust her judgment about the story. While we see the evidence, can we still really say what was the fact and what was not.
In any case, I wouldn't mind seeing Moore elaborate Neonomicon a bit more. It definitely left an opening for continuation. And that continuation it has gotten in the form of Providence. I'll be definitely checking that out at some point.
Neonomicon has sex, violence, and horror in it, so be warned if you're not into that kind of thing. But if you don't mind, grab it from Comixology. Or dig it out as a printed comic if you swing that way.