In this paper, I will discuss the conceptual foundation of agentoriented software development by relating the fundamental elements of the agentoriented view to those of other, well established programming paradigms, especially the object-oriented approach. Furthermore, I will motivate the concept of autonomy as the basic property of the agent-oriented school and discuss the development history of programming paradigms that lead to this perspective on software systems. The paper will be concluded by an outlook on how the new paradigm can change the way we think about software systems.