A number of trends, pressures and policy shifts can be identified that are promoting greater patient involvement in health care delivery through consultations, treatments and continuing care. However, while the literature is growing fast on different methods of involvement, little attention has been given so far to the role which patients themselves wish to play, nor even of the conceptual meanings behind involvement or participation. This article reviews the current models of involvement in health care delivery as derived from studies of professional views of current and potential practice, prior to examining the empirical evidence from a large-scale qualitative study of the views and preferences of citizens, as patients, members of voluntary groups, or neither. Individual domiciliary interviews were carried out with 44 people recruited from GP practices in northern England. These respondents were then included in a second phase of 34 focus groups in 6 different localities in northern and southern England, of which 22 were with individuals unaffiliated to any voluntary/community groups, 6 related to local voluntary/community groups with specific interests in health or health care, and 6 related to groups without such specific interests. A final set of 12 workshops with the same samples helped to confirm emergent themes. The qualitative data enabled a taxonomy of patient-desired involvement to be derived, which is contrasted with professional-determined levels of involvement identified from the literature. Participation is seen as being co-determined by patients and professionals, and occurring only through the reciprocal relationships of dialogue and shared decision-making. Not everyone wanted to be involved and the extent to which involvement was desired depended on the contexts of type and seriousness of illness, various personal characteristics and patients' relationships with professionals. These levels are seen to provide basic building blocks for a more sophisticated understanding of involvement within and between these contexts for use by professionals, managers, policy-makers and researchers.