The dominant social theory used by archaeologists has tended to focus on either small scale agency or large-scale cultural patterns and processes of change. The authors of this volume argue that archaeologists should use nonlinear models to more accurately model the connections between scales of analysis, and show how micro-scale variation can lead to macro-scale cultural change. This work examines the applications of nonlinear systems models within archaeology and evaluates the range of approaches currently encompassed within Complexity Theory.