This book aims to engage with one of the more pressing issues in the contemporary world, namely migration, either forced or voluntary. It intends to do so by focusing on the wellbeing of migrants and the role of religion in processes of integration in host societies. The book brings together researchers from various disciplines taking on the challenge to elaborate on the theme of this book from different perspectives, using different methods and theories. The value of multidisciplinary research on the role of religion in a globalised society – locally, nationally and internationally – can hardly be overestimated. Religious aspects and actors are present in legal, political and social policy contexts and form the basis for future research on e.g. secularisation, democracy, minorities, human rights, welfare, healthcare and identity formation. These and other related topics are discussed in this book. This introductory chapter provides the theoretical foundation for the book and its contributions