This Gothic novella tells the story of a young woman's susceptibility to the attentions of a female vampire named Carmilla. Carmilla predates Bram Stoker's Dracula by 25 years, and has been adapted many times for cinema. Although Carmilla is a lesser known and far shorter Gothic vampire story than the generally-considered master work of that genre, Dracula, the latter is heavily influenced by Le Fanu's short story.

Carmilla is an 1872 Gothic novel by Irish author Joseph Sheridan Le fans and one of the early works of vampire fiction, predating Bram Stoker's Dracula (1897) by 26 years. First published as a serial in the dark Blue (1871–72), the story is narrated by a young woman preyed upon by a female vampire named carmilla, later revealed to be mircalla, Countess karnstein (carmilla is an anagram of mircalla). the character is a prototypical example of the lesbian vampire, expressing romantic desires toward the protagonist.

An adaptation of Shaftesbury's award-winning, groundbreaking queer vampire web series, Carmilla. Newly escaped from the stifling boredom of a small town, college freshman Laura is ready for her first great adventure. But when her roommate, Betty, vanishes, and a sarcastic, nocturnal philosophy student named Carmilla moves into Betty's side of the room, Laura decides to play detective. Turns out, Betty isn't the first girl to go missing--she's just the first girl not to come back. As Laura closes in on answers, tensions rise with Carmilla. Is this just a roommate relationship that isn't working out, or does Carmilla know more than she's letting on about the disappearances? What will Laura do if it turns out her roommate isn't just selfish and insensitive, but completely inhuman? And what will she do with the feelings she's starting to have for Carmilla?

Le Fanu worked in many genres but remains best known for his mystery and horror fiction. He was a meticulous craftsman and frequently reworked plots and ideas from his earlier writing in subsequent pieces. Many of his novels, for example, are expansions and refinements of earlier short stories. He specialised in tone and effect rather than "shock horror", and liked to leave important details unexplained and mysterious. He avoided overt supernatural effects: in most of his major works, the supernatural is strongly implied but a "natural" explanation is also possible. The demonic monkey in "Green Tea" could be a delusion of the story's protagonist, who is the only person to see it; in "The Familiar", Captain Barton's death seems to be supernatural, but is not actually witnessed, and the ghostly owl may be a real bird. This technique influenced later horror artists, both in print and on film (see, for example, the film producer Val Lewton's principle of "indirect horror").

Though other writers have since chosen less subtle techniques, Le Fanu's best tales, such as the vampire novella Carmilla, remain some of the most powerful in the genre. He had enormous influence on one of the 20th century's most important ghost story writers, M. R. James, and although his work fell out of favour in the early part of the 20th century, towards the end of the century interest in his work increased and remains comparatively strong.