Jacques Ranciere's first major work, Althusser's Lesson appeared in 1974, just as the energies of May 68 were losing ground to the calls for a return to order. Ranciere's analysis of Althusserian Marxism unfolds against this background: what is the relationship between the return to order and the enthusiasm which greeted the publication of Althusser's Reply to John Lewis in 1973? How to explain the rehabilitation of a philosophy that had been declared `dead and buried on the barricades of May 68'? What had changed? The answer to this question takes the form of a genealogy of Althusserianism that is, simultaneously, an account of the emergence of militant student movements in the `60s, of the arrival of Maoism in France, and of how May 68 rearranged all the pieces anew. Encompassing the book's distinctive combination of theoretical analysis and historical description is a question that has guided Ranciere's thought ever since: how do theories of subversion become the rationale for order?