Agent-based modeling/simulation is an emergent approach to the analysis of social and economic systems. It provides a bottom-up experimental method to be applied to social sciences such as economics, management, sociology, and politics as well as some engineering fields dealing with social activities. This book includes selected papers presented at the Fifth International Workshop on Agent-Based Approaches in Economic and Social Complex Systems held in Tokyo in 2007. It contains two invited papers given as the plenary and invited talks in the workshop and 21 papers presented in the six regular sessions: Organization and Management; Fundamentals of Agent-Based and Evolutionary Approaches; Production, Services and Urban Systems; Agent-Based Approaches to Social Systems; and Market and Economics I and II. The research presented here shows the state of the art in this rapidly growing field.