The book is divided into six parts, providing the reader with introductory material concepts, and techniques that have provided the results to practical use, and research that is still more investigative in nature: Part I introduces different aspects of AOSE research and explain why the agent-based approach fits for the development of complex software systems, Part II presents three-Gaia methodology, tropos, and Mase, who has been proposed as a general-purpose approach to guide the development of complex MAS, Part III shows four extra-ADELFE methodology, MESSAGES, SADDE, and the Prometheus- which show interesting characteristics that make them suitable for the development of MAS special classes, such as MAS adaptive and intelligent agent-based systems are intentional, and for the development of specific application areas, such as telecommunications and market agents, Part IV shifts the focus of the methodology for infrastructure and equipment. conceptual tools such as FIPA and AUML standard, plus infrastructure software such as a tuple-based and JADE, is one of the most promising available to developers, concentrating on innovative approaches to engineering agent-based systems, starting from different assumptions and radical concepts from the traditional concept adopted in software development who rely on self-organization and biological principles or physical solutions are inspired, like a swarm intelligence, amorphous computing, adaptive MAS, and online engineering open systems, Nally, Section VI describes two scenarios appear to take the benefits of MAS technology-Grid and Ubiquitous Computing.