In the 19th century missionary advocates argued that cross-cultural mission would bring a reflex action that would benefit the Western church. The mission impulse would rebound back on the sending church and it would reap benefits of this missionary activity. Today in the post-colonial period this dynamic is becoming increasingly evident. Western theology, liturgy, and ecclesial structures and practice, were formed in a time when the church did not understand her missionary nature. Today we are beginning to understand that mission is not simply one activity of the church but belongs to the very core of its existence. This insight is beginning to revolutionize theology and ecclesial life. Lesslie Newbigin embodies reflex action.= From forty years of missionary experience in India he brings the Biblical perspective of mission to bear on the Western church. This book examines Newbigin's missionary ecclesiology elaborating the relation of the church to the mission of God, to its own nature and calling, and to its religio-cultural context. It is a call to rethink our ecclesiology and church practice in Western culture.