Systems thinking has evolved over the millennia as people have looked for ways to articulate the features of the world around them in a coherent manner.1 Starting from the definition of a system as an integrated whole made up of interconnected parts, various formalizations of systems thinking in a way that would be of interest to managers have emerged over time as people have looked for ways of rationalizing their interactions with the world. These formalizations give us a set of ontological and epistemological devices that have been used to define what the world is, to explain how it works, and to define and justify interventions that are intended to change, control or constrain the future behaviour of that world.The ancients debated the role of structure, form and composition in determining the behaviour of social, physical and natural systems, and engaged with the transience of system phenomenology, and we find these themes recurring in modern theories of systems behaviour. Successive schools of systems thinking have focused on specific aspects of systems properties, and developed an apparatus to confront the challenges of their time in dealing with complexity.In this chapter we track the evolution in the Western scientific tradition of systems ideas to deal with complexity, and reflect on the developments that are most likely to be influential in shaping management thinking from here on.Our account takes us from Bertalanffy's biologically inspired GST (General Systems Theory), through the cybernetics of the Macy Group and the analytical ethos of systems engineering, the theories of self-organization and self-production in chemistry and life, to the present day engagement with the ideas of complexity science.This trajectory crosses and re-crosses traditional divisions between the physical, biological and chemical sciences, and it takes us from the Newtonian predictability of the trajectories of complex dynamical systems in space to the present day challenges of dealing with the unpredictable trajectories of ...