This is an explication of Lacan’s Seminar XVII. The introduction situates the Seminar in its time and in relation to other theories of discourse. In part one I examine the changes which it brings to a variety of ideas already known in Lacan’s oeuvre such as Jouissance, Master Signifier(s) and Oedipus. Part two looks the four discourses in detail after considering the positions common to each. I provide accounts of each discourse as taking place internally to a subject and between subjects. The coda examines areas where further research is possible, reviews and critiques some scholarship on this seminar and inquires into the use value of the discourse theory, both generally and as a means of getting beyond Lacan.