This book examines the contribution made to those debates by Karl Rahner (1904-84), one of the foremost Catholic theogians of this century. The book situates Rahner's ecclesiology in the context of his whole theology focusing in particular on the evolution of his thought over a fifty-year period. Dr. Lennan shows how Rahner's approach to the Church was radicalized by his awareness of the rate of social change in the twentieth-century.