TAEMS: A Framework for Task Analysis, Environment Modeling, and Simulation. Formal approaches to specifying how the mental state of an agent entails that it perform particular actions put the agent at the center of analysis. For some questions and purposes, it is more realistic and convenient for the center of analysis to be the task environment, domain, or society of which agents will be a part. We are constructing such a task environment-oriented modeling framework that can work hand in hand with more agent-centered approaches. In our approach, careful attention is paid to the quantitative computational interrelationships between tasks, to what information is available (and when) to update an agent’s mental state, and to the general structure of the task environment rather than single-instance examples. A task environment model can be used for both analysis and simulation; it avoids the methodological problems of relying solely on single-instance examples, and provides concrete, meaningful characterizations with which to state general theories. To date we have constructed models in the context of cooperative distributed problem solving and real-time scheduling. We are now working on computational models of organizations such as hospitals, managing software engineering projects, and distributed / multi-agent information retrieval.