In the years since the Second Vatican Council, the Catholic Church has struggled to renew its self-understanding and revise its relationship to the world. This book examines the contribution made by a key figure in those debates, Karl Rahner (1904-1984), one of the foremost Catholic theologians of this century. Lennan analyzes Rahner's ecclesiology in the context of his whole theology, charting both the development of his thought and, particularly, his vision of the Church's future.