Personalisation of documents offers the promise of better support of users. Such personalisation relies on a model of the user. This paper describes the Personis user model server. The novel and defining characteris- tic of Personis is that it was designed around the requirement that users be able to scrutinise and control their user models. The paper reviews the need for a scrutable user model server. To illustrate the operation of the server, the paper provides an overview of the way it oper- ates in conjunction with an application system which provides a personalised jazz music service. Finally, we discuss previous work, indicating how it relates to the Personis project.