What are the fundamental attributes of the Catholic Church? What is the source from which it has drawn vigor and life through its two thousand years of life on earth? What are the secret sources of its incredible vitality in the world today? Karl Adam brilliantly answers these and many other questions about the nature and structure of the Church. Writing with great force and clarity, he examines the essential nature of the Catholic Church from the basic premise that it was expressly founded by Christ, traces its historical development and analyzes actual functioning through the ages.