This dissertation seeks to reactivate the Marxist transition debate, by conceptualising transition as a problem in its own right, moving away from a stagist vision of the development of modes of production. Part I outlines the historical materialist parameters of the ontology of transition, and traces the concept across classical and western Marxism. This section draws from Althusserian theory to sketch out a conception of historical time as a multiplicity of dislocated trajectories. This is followed by a critique of post-Marxism, based on the disappearance of the concept of transition in the discursive turn. It is argued that transition should be retained as a sociologically rigorous concept, and that among various strands of Marxist theory there is evidence of its efficacy. Part II analyses contemporary left theory and politics through the dichotomy of melancholy and utopia, and argues that they exemplify temporal complexity and illuminate current impasses on the left. Part III applies the findings of the preceding parts to strategic questions of demands, agency and strategy. This is achieved through a substantive discussion of postwork theory as a new postcapitalist vision, embodying issues of temporality, transition and utopia. The thesis concludes that the neglected problem of transition and the notion of multiple temporalities are important theoretical tools for addressing questions of historical epistemology and left strategy. Understanding transition as an embedded societal tendency is valuable to critical social theory, and provides the means to theorise postcapitalist futures.