Written and revised over the course of twenty years, Louis Althusser’s Machiavelli and Us remains perhaps his most unfinished work. Fragmentary, replete with corrections in turn revised, deleted and restored, this is an essay poised on what Althusser termed in the mid-1960s ‘a theoretical conjuncture’. How unlikely the attraction of one of the most structuralist of Marxists to Machiavelli; Althusser was after all par excellence the theorist of totalities that arrogated questions of agency and action to themselves, describing the latter as mere epiphenomena of the tectonic movement of capitalist structures. What is it that attracts this theoretician of invariant structures to Machiavelli’s singular conjunctures and the fleeting figurations of virtù? And yet, by the time Althusser comes latterly to write this treatise on constituent power, he finds Machiavelli’s ‘endeavour to think the conditions of an impossible task’ as the one he too must confront. ‘Machiavelli’s question, the question how to begin from nothing, was my own.’2