Every great book that gets adapted to a movie/series and then they use the posters from the adaptations as book covers.

*final boss music starts*

I personally think the short stories make a really good introduction. Mostly because they tend to focus much more on evoking feelings than actually following a plot.

The first story I ever read was "The Nameless City". There is nothing particularly special about it, it's definitely not the best one, but to this day I really love it as an introduction, because at its core, it's a short summary of what "all the hype" is about: The awe and hopelessness in the face of something that's adjacent to humans, but much older and frightening.

Or, if someone wants to go straight to the meat, "Colour Out of Space" works wonderfully for a first time reader.... with the problem being that it's really fucking good and you can't get much better than that, so anything you read after will end up being judged against it.

But... if I had heard people hyping up Cthulhu my whole life as this unimaginable elder god, and read it as my first story just to have him >!being run over by a fucking boat and going back to sleep!<, I'd probably be like... really? that's it?

I'll say the same thing I said in another Lovecraft-related post a little while ago:

It's an unpopular opinion, but I think The Call of Cthulhu might be one of the worst possible introductions to H.P Lovecraft.

Because, despite its namesake, this might be the one story that goes out of its way to make the mythos as mundane as possible, with probably one of the worst and most anti-climatic endings he has ever written.