Psychoanalysis was the most important intellectual development of the 20th century. Alain Badiou described psychoanalysis as an ’antiphilosophy’: a practice that offers the strongest possible challenges to thought. Now, Justin Clemens examines psychoanalysis under this rubric. He shows how this impacts on the key concepts that continue to be misrepresented by disciplines hostile to psychoanalysis; above all, regarding the relationships of humans to drugs, animality and sexuality.