This chapter describes Tutor3, the latest in a sequence of systems that we have created to provide adaptation of hypertext where the user can maintain a real sense of control over the adaptivity. In Tutor3, the user always has access to precise details of what has been adapted to them, how this adaptation is controlled, and they can alter it. We describe both the user’s and the hypertext author’s view of the system. We then report a qualitative evaluation of the system in terms of the ways that users were able to understand both the adaptation and their power to control it. We conclude that while users do expect adaptivity, they do not expect to be able to control it. We discuss the challenges this creates for building adaptive systems that users can control effectively.