This critical review of Foucault's four books, Madness and Civilization, The Birth of the Clinic, The Order of Things, and The Archeology of Knowledge, does much to clear up the obtundities and confusions which are likely to bother the reader of Foucault's special brand of philosophy, linguistics, history, and structural analysis. Leary does a splendid job of elucidating Foucault's place as a thinker in regard to the humanistic sciences.