This text is an overview of literature relevant to the development and modelling of interactive systems. It is the most comprehensive part of the documentation I made during the literature research stage of my PhD project, which should result in a modelling framework for interactive systems. More precisely, the scope of this project is natural language, multimodal, and virtual reality systems, and ways of modelling the dynamics of interaction of such systems for the purpose of aiding system development. The topics addressed in this text naturally include existing systems and modelling techniques, but theoretical frameworks and methodological issues are also addressed. Short introductions are given to cognitive psychology, semiotics, communication models, and HCI. Systems and strategies are reviewed, covering the topics multimodality, redundancy and confirmation, and ways of modelling dialogue and task structure. Methodological issues are reviewed, in particular some methodologies, and strategies for design/implementation and analysis/evaluation. Finally, some conclusions are given, as well as an indication of the directions of my future research.1