This chapter examines a seminal text in the emergence of detective fiction as a new popular literary genre, Poe’s The Murders in the Rue Morgue. Published in 1841, and occupying an ambiguous epistemic stance between the rational and the marvellous, as with much of Poe’s writing, the narrative explicitly confronts the reader with the philosophical question: how can we know? Not just the practical ... [Show full abstract] question of ‘whodunnit?’; but what is the basis of our knowledge claims when confronted with a mystery that appears to defy the laws of nature? How can two persons be cruelly murdered in such a horrific fashion inside a closed and locked room to which no other person had access without relying on metaphysical explanations such as witchcraft? The authorial use of a non-human perpetrator of the gross deed only adds to the epistemic tension between witchcraft and science that the text implicitly confronts.