Agent-Based Modeling/Simulation (ABM/ABS) is an emerging field that enables bottom-up and experimental analysis in social sciences such as economics, management, sociology and politics. The chapters of this book are the selected papers from those presented the Third International Workshop on Agent-Based Approaches in Economic and Social Complex Systems held in Tokyo, Japan in 2005. Articles in this book covers methodological issues, computational model/software, combination with gaming simulation, and real-world applications to economic, management/organizational and social issues.