In the context of social and religious pluralisation, establishing the relationship between religion, religious actors, and the secular state is challenging. And while religion is not only a potential source of meaning for individuals, it is also of public significance, with still large Christian churches, along with other religious communities and their institutions, continuing to perform important functions in society. However, due to increasing secularisation and a decline in church membership, the traditional rights of religious communities are becoming less widely accepted. The transformation of religious sociological milieus and affiliations necessitates significant adjustments to the law and organisation of shrinking religious communities. This volume brings together contributions from the last two decades that address these developments from the perspective of constitutional law on religion and Protestant church law.