A substantial part of Pierre Klossowski’s philosophical writings is dedicated to the works of Marquis de Sade, but Sade’s influence can also be traced in his literary and visual oeuvre. In his play Roberte, ce soir, Klossowski dramatizes scholarly Octave’s quest for the ultimate realization of his wife Roberte. He wants Roberte to be actualized as the Roberte, Roberte le signe unique. The play shows Octave’s unrelenting attempts to realize a Roberte without lack. He creates his own laws and revises existing theories beyond their limits in order to reach his goal. The author argues, using Lacan, that an analysis of Klossowski’s play Roberte, ce soir reveals the structure of perversion. As Lacan indicates, the pervert disavows castration. He does so by situating himself in the place of the lack for the other, in an attempt to behold the other’s enjoyment. Klossowski’s work, the author argues, can be conceptualized as a dramatic staging of the central issue of the pervert’s relation to the other.