In software engineering, task models are one means to support the overall software design process. Thorough task analysis and a carefully engineered task model can improve the usability of a software product and may be re-used in assistants and user interface agents to support users during specific, possibly complex tasks within the application. Unfortunately, in real life task models can hardly be found in their proper specification but exist rather informally or implicitly in other descriptions. Thus, we need to find a way to reverse-engineer task models from existing applications in order to be able to use them as a basis in our assistance scenario. This paper describes how a general task model of how to compose an e-mail message was derived from specific applications imple­menting this task.