Book excerpt: Making systems easier to use implies an ever increasing complexity in managing communication between users and applications. Indeed an increasing part of the application code is devoted to the user interface portion. In order to manage this complexity, it is important to have tools, notations, and methodologies which support the designer’s work during the refinement process from specification to implementation. Selected revised papers from the Eurographics workshop in Namur review the state of the art in this area, comparing the different existing approaches to this field in order to identify the principle requirements and the most suitable notations, and indicate the meaningful results which can be obtained from them.