The European Christianity is becoming more international and plural. In Germany alone, there are over 10 million Christians with a migration background. Many of them organize themselves in migration churches, international and intercultural congregations that enrich religious life in a sustainable way. Nonetheless, migration churches are a stepchild in religious studies and theology. The present volume makes the phenomenon accessible systematically and comprehensively. It emerged from several years of collaboration between religious scholars and theologians and explores the possibilities that the migration of Chritians opens up for theology and the church.