Knowledge, Ideology, Reproduction is the first book-length examination of the theses developed by Louis Althusser and his collaborators on the processes of class-based educational formation and the function of schools. Drawing largely on unpublished writings that have been overlooked by scholars of both Althusser and critical pedagogy, this study reveals that, for Althusser and the groupe Spinoza, educational formation and the position of knowledge are central, decisive issues in understanding the real forces driving the mechanisms of social reproduction. This perspective enables a critical interrogation of knowledge transmission and opens up new possibilities for transformative educational practices.