Joseph Thomas Sheridan Le Fanu (; 28 August 1814 – 7 February 1873), often shortened to J. S. Le Fanu, was an Irish writer of Gothic tales and mystery novels. He is considered by literary critics to be among the greatest ghost story writers of the Victorian era, as several of his works were central to the development of the genre. In addition to short stories, Le Fanu was also the author of novels such as Uncle Silas (1864), macabre poems, and the collection of five stories In a Glass Darkly (1872), in which the novella Carmilla (1872) is significant as a foundational work of vampire literature. Born into a family of writers, Le Fanu began writing poetry at the age of fifteen, using his father's personal library to educate himself. Due to severe financial constraints, his family were forced to sell the library and its books to settle some of their debts following the death of his father.