School of Electronics and Computer Science Faculty of Engineering , Sciences and Mathematics University of Southampton

User Modelling is the core component of every personalisation service provided to various groups of users in an attempt to utilise available recourses in the best possible way. While researching the literature, one can recognise that User Modelling had its first appliance in the area of Intelligent Tutoring and Adaptive Hypermedia Systems, especially in the educational context. With the introduction of the World Wide Web and later of the Semantic Web, User Modelling could not be restricted to standalone and online applications; therefore, it was incorporated in the Semantic Web research. It became the most important factor in the effort to personalise a diversity of web resources according to the users' needs. While trying to move a step further and model a dynamic user in a variety of contexts, lifelong User Modelling, the ability to model a dynamic and changing user throughout lifetime interactions with a diversity of resource providers, appears to be an attractive solution and it has been introduced in this report. Although some significant developments led the progress in this area, the big picture is still blurry. This, as expected, results in further research, required to provide solutions to existing and arising challenges.