In the last half century new religious movements or cults of one sort and another have mushroomed throughout the US and Europe. Increasingly these groups have been met with attempts to monitor and control them on the part of the state, and concerns about the protection of religious 'consumers' have been set against the democratic right to religious freedom. In this collection, leading sociologists of religion from the UK, US and across Europe, reflect on the important work of Eileen Barker in this field, and debate the political, practical and ethical issues which arise from these changes in the religious landscape. Contributions also attempt to make sense of the elusive social dimensions of religion, in addition to presenting challenges to religion in the form of questioning ideas and practices that may be taken for granted in some religious circles.