Agent based computing is rapidly emerging as a powerful technology for the development of complex software systems, synthesizing contributions from many different research areas including artificial intelligence, software engineering, robotics and distributed computing. Developing applications in terms of autonomous software agents that exhibit proactive and intelligent behavior, and that interact with one another in terms of high level protocols and languages, leads to a new programming paradigm. Agent based software engineering offers some promising benefits over used in mainstream software engineering. First of all it promises to solve the interaction bottleneck decreasing the complexity of engineering software. Secondly it promises to decrease the difficulties involved in designing systems for complex environments. The latter claim is based on the qualitative argumentation that multiagent systems are well suited for such environments, or at least that the agent-oriented mindset promotes good design practice.