The book contains five parts. Part I, Complex decision making: Concepts, theories and empirical evidence, has two chapters. It examines the nature and the dimensions of decision making and learning in dynamic task, based on published literature. Part II of the book, Tools and techniques for decision making in complex systems, consists of six chapters and deals with the range to tools, methods, and technologies that support decision making in complex, dynamic environments including Method of Dynamic Handling of Uncertainty, System Dynamics, System Dynamics and Multiple Objective Optimization based hybrid approach, Object Oriented Programming based simulation methods, Data Envelop Analysis, Group Model Building, and Agent-based Modeling that can help people make better decisions in complex systems. Part III of the book, System dynamics and agent-based modeling in action has five chapters and provides the empirical evidence to the application of both modeling approaches to variety of complex decision making situations covering both individual and group decision making perspectives. In part IV of the book, Methodological issues in research on complex decision making, the two chapters deals with the two key issues: (i) understanding of “goal dynamics” and, (ii) measure of change in the mental models of the decision makers in dynamic tasks. Part V of the book, Future directions on complex decision making, discusses the emerging trends and challenges in using modeling and model based tools for improved decision making in complex, dynamic environments.