<i>Confusion of Tongues</i> describes the genesis of Freud's clinical anthropology. A careful reading of Freud's early texts and letters to Fliess illustrates how Freud abandons his seduction theory of the neuroses in favor of a sexual biology. The meaning and the implications of this 'biological turn' are made clear through an analysis of Freud's <i>Three Essays on the Theory of Sexuality</i>, first published in 1905. This 'biological turn' leads to three mutually dependent claims that are fundamental to Freud's project of a clinical anthropology: the primacy of (infantile) sexuality, the discontinuity between the world of the adult and the world of the child, and the continuity between 'normality' (psychic health) and pathology.<br><br>In the later editions of <i>Three Essays</i>, Freud increasingly stresses the continuity between infantile and adult sexuality, thus undermining the radical character of his previous claims. <i>Confusion of Tongues </i>shows that the introduction of the Oedipus complex plays a crucial role in this evolution. The book also attempts to resolve the resulting impasse through a confrontation of Freud's work with the work of Ferenczi and Laplanche. For both Ferenczi and Laplanche, Freud's clinical anthropology gets its foundation from his theory of sexual trauma. However, van Haute and Geysken's careful reading of their texts makes clear that neither Ferenczi nor Laplanche succeed in providing a new theoretical foundation for Freud's original claim that sexuality is the weak spot in human nature that predisposes us to psychopathology. <i>Confusion of Tongues</i> therefore argues that the shibboleth of psychoanalysis is not so much the primacy of sexuality, but the discontinuity between the world of the adult and the world of the child. Philippe van Haute is a professor of philosophical anthropology at the University of Nijmegen (The Netherlands). He is the president of the Center for Philosophical Anthropology and Psychoanalysis (University of Nijmegen/University of Leuven) and a practicing member of the Belgian School for Psychoanalysis.