The Castle of Otranto by Horace Walpole was the original gothic story in the English language. For being the first it isn't exactly “there” yet, I would describe it as part Arthurian succession-crisis melodrama and part Shakespearean tragedy. Link goes to Archive.Org
Northanger Abbey by Jane Austen is a personal favorite of mine. There was a 2007 film adaptation that's very faithful to the book except for adding just a dash of implied spice a couple of times (Jane Austen would never) and raising the stakes a couple of other times, so if for whatever reason you have difficulty getting through Austen's prose then I recommend the 2007 movie.
The Vampyre by John William Polidori — So in 1816 the weather was so terrible that famous poet Lord Byron stayed indoors with a group of friends and they would read aloud ghost stories while it rained outside. Someone said “let’s write our own ghost stories” and Lord Byron went like ”that’s a cool idea” (not actual quote) and by the next year there were two submissions to this challenge and neither of them were about ghosts. This is one of those submissions. The other was Frankenstein by Mary Shelley, but Frankenstein is quite a bit lengthier than The Vampyre if you compared them so I'm sort of also listing by length.
Wuthering Heights by Emily Brontë. I heard rumors that this was difficult to read? It's got nested narratives, but I didn't think it was difficult. I think I finished reading this one in like three days, compared to another gothic novel by a Brontë sister... Jane Eyre by Charlotte Brontë took me like a week and it was a solid story but paced like molasses. There's something way more breezy and atmospheric (pun intended) about Wuthering Heights that I recommend it more but apparently it's a wildcard depending on your reading style preference.
The Phantom of the Opera by Gaston Leroux but I only liked this story after reading the Lowell Bair translation. The translation by De Matthos made me think this just not very good. The Lowell Bair translation is not uncontroversial but it is definitely superior — and sort of epistolary, so the same reading-style-preference warning as Wuthering Heights applies. It is a common gothic-novel thing to have some framing devices of document-discovery or epistolary though. There is a very very very popular stage musical adaptation but I really do think that this 2011 recording of the stage performance is so very much better than the 2004 movie version. It still leaves out a lot of the comedy between the new opera-house managers and makes Raoul de Chagny less of a jerk (when that was kind of an interesting part of the young viscount's character.)
Longer works that might get in the way of your reading fifteen gothic novels in one summer but that I think is worth the time:
Sherlock Holmes novel/short-stories series by Sir Arthur Conan Doyle. The “core myth” texts are: A Study in Scarlet, The Sign of the Four (Dr. Watson meets Mary Moran in this one and spoilers she becomes Mrs. Watson), The Hound of the Baskervilles, and The Valley of Fear. I would say that The Hound of the Baskervilles has the most gothic vibe out of all of them, but I can also recommend super-speedrunning by skipping to The Adventures of Sherlock Holmes short story collection and going for “The Adventure of the Copper Beeches” within that collection—one very short story, done.
The Last Man by Mary Shelley. It's not haunted-house gothic and it's not monster-gothic and it's so very lengthy but I love this one, I think it's so underrated! The first half is an Otranto-style succession-crisis melodrama, the second half is like a switch flipped and now everyone has to deal with like 3 different kinds of Apocalypse happening at the same time — it’s wild!
The Hunchback of Notre-Dame by Victor Hugo (Walter Cobb translation). I finished reading this one in 5 days. Moby-Dick by Herman Melville was in the same word-count range but that one took me like two and a half months to finish reading. I didn't mind the digressions into how important architecture preservation is.
The Picture of Dorian Gray by Oscar Wilde. What Jane Eyre is to me (solid unit of a story but ploddingly-paced), Dorian Gray is to many other people. If you did like Dorian Gray and don't mind period-accurate violence and casual racism, then I actually would recommend reading Orlando by Virginia Woolf right afterwards because it's samevibes and I think was slightly more whimsical and florid and it put more clearly its exploration of the artistic process and the perils of living in a society...whereas Dorian Gray was getting at something but I felt like it was being too fuzzy around the edges.
Contemporary gothic novels at a reasonable length:
The Haunting of Hill House by Shirley Jackson. I imprinted on the 1963 film adaptation like I was a duckling, and the book version has such limpid prose and really got immersive into Eleanor's low-key angst and high-key neurosis.
Middle of the Night by Riley Sager, gothic in the sense of being a location-focused missing-person or murder mystery. Riley Sager is hardly the second coming of Agatha Christie in terms of airtight plot and clear prose, but if you're into pulpy goth-adjacent genre works then I think of this one as the perfect summer read.
Everything, Everything by Nicola Yoon. The twist made this very unpopular back in the day, and it's not marketed as gothic, but hear me out: document-discovery epistolary framing device, guardian/parent who does not have the main girl's best interests at heart, haunted by the past, subversion of madwoman in the attic trope (she's not locked away in the forbidden room because she's mad, she's gone mad because she's been locked away in the forbidden room.)
