Agent systems are being used to model complex systems like societies, markets and biological systems. In this book we investigate issues of agent systems related to convergence and interactivity using techniques from agent based modelling to simulate complex systems, and demonstrate that interactivity/exchange and convergence in multi-agent systems are issues that are significantly interrelated.Following are the topics and features: it introduces the state of the art in multi-agent systems, with an emphasis on agent-based computational economics; sheds light on the fundamental concepts behind the stability of multi-agent systems; investigates knowledge exchange among agents, the rationale behind it and its effects on the ecosystem; explores how information provided through interaction with the system can be used to optimise its performance; and, describes a pricing strategy for a realistic large-scale distributed system. This book supplies a comprehensive resource and will be invaluable reading for researchers and postgraduates studying this topic.