The teachings of psychoanalysis have shown, notably with Freud and Lacan, that truth has the structure of fiction. This thesis is surprising, considering the contemporary definition of truth reduced, by the discourse of science, to its objective quality. In contrast to this apprehension of the register of truth, Lacan defines truth as a place and situates it on the side of the fictional, under the species of myth. The literature of science fiction then asserts itself as a relevant material to analyze the relation of the discourse of science to truth. It is for this reason that we return to the life and work of H. P. Lovecraft, a prolific writer of the 20th century. We show that his horrific stories can be read as a consequence of the products of the science of his time. His personal journey sheds light on both the subjective function that fictional writing carries with it, but also how a work of fiction can take on the value of truth. The posthumous success of Lovecraft’s work thus testifies to the topicality of a contemporary horror that the writer had worked to circumscribe throughout his life.