The international religious networks explored in this volume range from the cults of early medieval saints to the ecumenical networks and friendships which developed in the twentieth century. The essays reveal the diversity of religious networks over the centuries and engage with enduring questions that transcend national, geographical and sectarian boundaries. Networks could be of ideas or of people but most commonly involved both. They could be supported through formal organizations, institutions and bureaucracies or through more informal personal ties, such as friendships and acquaintances. Some international networks sustained a particular interest group, sect or denomination; others aspired to be ecumenical and all-encompassing. Networks might be created by, or around, a single individual; they could span an entire institutionally organized church; or, potentially, they could hope to include the whole of Christendom or even aim to connect a range of different world religions. Networks might be made up of largely like-minded individuals sharing largely similar perspectives, or they could bring diverse individuals and groups together to focus on a specific religious issue, concern or personality. The book offers answers to the following questions. How far has religion, both in terms of the ideas it creates and in terms of its practitioners and adherents, been especially good at forming international networks? What is it about religion that gives it such leverage and such an ability to transcend national and regional boundaries and divides? These questions have some relevance for our understanding of the networks sustained by different religious faiths at the present time, as well as for understanding the strains in keeping international religious networks intact. Jeremy Gregory is Professor of the History of Christianity at the University of Manchester; Hugh McLeod is Emeritus Professor of Church History at the University of Birmingham.