Psychoanalysis was the most important intellectual development of the twentieth century, which left no practice from psychiatry to philosophy to politics untouched. Yet it was also in many ways an untouchable project, caught between science and poetry, medicine and hermeneutics. This unsettled, unsettling status has recently induced the philosopher Alain Badiou to characterise psychoanalysis as an ‘antiphilosophy’, that is, as a practice that issues the strongest possible challenges to thought. Justin Clemens takes up the challenge of this denomination here, by re-examining a series of crucial psychoanalytic themes: addiction, fanaticism, love, slavery and torture. Drawing from the work of Freud, Lacan, Badiou, Agamben and others, ‘Psychoanalysis is an Antiphilosophy’ offers a radical reconstruction of the operations and import of key psychoanalytic concepts and a renewed sense of the indispensable powers of psychoanalysis for today.