On the occasion of the publication of this very recent book, "Lacan: le fourvoiement linguistique. La métaphore introuvable," - 'The Linguistic Error: The Lost Metaphor' - (Presses Universitaires de France, 2003), written by the psychoanalyst, A. Costes, we reexamine Lacans' article, "la lettre dans l'inconscient." ('The letter in the unconscious'). We show that if Lacan were wrong, as Costes claimed, his mistake lies not so much in considering, misguidedly, Freud's 'condensation' as metaphor & 'displacement' as metonymy, as in using categories established in structural linguistics (by such linguists as Roman Jakobson) to describe the dream story in psychoanalysis which demands a pragmatic frame. We then show that Costes's criticism aims at promoting a practice in psychoanalysis which would control meaning, as naturalist rhetoric tried to do. Lacan's intuition led him to consider the deployment of meaning within discursivity so that he seems closer to Freud's logic than his critic, who claims to adhere to it so strictly. (LLBA, Accession Number 200509748, (c) CSA [2004]. All rights reserved)