A theory of the creation and reproduction of social systems that is based in the analysis of both structure and agents, with neither being more important than the other. This is the duality of structure, where both the agent and structure interact to bring about social change. Structure is not the main object of social research, but acts of structuration are. Lippuner and Werlen in N. Thrift and R. Kitchin, eds (2009) explain at length, but the abstract should be enough.