"The Facts in the Case of M. Valdemar" is a short story by the American author Edgar Allan Poe about a mesmerist who puts a man in a suspended hypnotic state at the moment of death.

An example of a tale of suspense and horror, it is also to a certain degree a hoax, as it was published without claiming to be fictional, and many at the time of publication (1845) took it to be a factual account.

He is interested in mesmerism, a pseudoscience involving bringing a patient into a hypnagogic state by the influence of animal magnetism, a process that later developed into hypnotism.

repeatedly, the narrator starts to bring him out of his trance, only for his entire body to immediately decay into a "nearly liquid mass of loathsome—of detestable putrescence."

[5] Collyer reported of the story's success in Boston: "Your account of M. Valdemar's case has been universally copied in this city, and has created a very great sensation.

"[6] Another Englishman, Thomas South, used the story as a case study in his book Early Magnetism in its Higher Relations to Humanity, published in 1846.

"[11] Elizabeth Barrett Browning wrote to Poe about the story to commend him on his talent for "making horrible improbabilities seem near and familiar".

[12] The Virginia poet Philip Pendleton Cooke also wrote to Poe, calling the story "the most damnable, vraisemblable, horrible, hair-lifting, shocking, ingenious chapter of fiction that any brain ever conceived or hand traced.

"[13] George Edward Woodberry wrote that the story, "for mere physical disgust and foul horror, has no rival in literature.

[15] Rudyard Kipling, an admirer of Poe, references "The Facts in the Case of M. Valdemar" in his story "In the House of Suddhoo", which suggests the disastrous results of the sorcery used by a man trying to save his sick son's life.

"[16] Poe uses particularly detailed descriptions and relatively high levels of gore in "The Facts in the Case of M. Valdemar", displaying his own studies of medical texts.

[17] Valdemar's eyes at one point leak a "profuse outflowing of a yellowish ichor", for example, though Poe's imagery in the story is best summed up in its final lines: "... his whole frame at once—within the space of a single minute, or even less, shrunk—crumbled—absolutely rotted away beneath my hands.

He has "no relatives in America", according to the text, and scholar María DeGuzmán suggested his name is "Galician-Portuguese" term which can be literally translated as "valley of the sea".

Stadler has also proposed that Valdemar represents a "shifty nationality" associated with 19th century mistrust and prejudice of Jews as people lacking their own culture and who "traffic in other's originality".

"The Facts in the Case of M. Valdemar" was adapted into film in Argentina in 1960 as a segment of Masterpieces of Horror, first shown in the United States in 1965.

[2] Narciso Ibáñez Serrador included an adaption into his Historias para no dormir (Tales not to sleep) in 1966, which he remade sixteen years later with the same actors, this time in color.