The purpose of this thesis is to analyze the different tools available for automatic help generation and to describe the Isolde project (Integrated Software and On-Line Documentation Environment), a new tool for writing on-line help. The objective of Isolde is to automatically generate hypertext based on-line help. This project exploits the common grounds between task model and system behavior models. A task modeling tool used to process a particular model has been implemented and is described in this thesis. The task modeling tool is aimed at importing a particular task model into a graphical form and easy to modify structure, then exporting the model in a format usable for natural language generation. An example is provided, together with a demo on disk.