The authors describe how Lacan diverged from classical Freudian concepts to arrive at an alternative model of psychoanalysis. In a discussion that also addresses the concept of the mirror stage and Lacan's use of language, the authors show how the Lacanian concepts of jouissance and the prohibition of incest contribute to this model, which can be successfully applied to the psychoanalytic treatment of more seriously disturbed patients. A clinical vignette is presented to illustrate the latter point.