From the foreword:
In this essay Mr. Marshall W. Baldwin presents his subject not merely as a political organization immersed in a struggle for temporal power, but rather as an all-pervasive aspect of mediaeval life itself. The papacy was no more the church than the empire was feudalism. The church was Christendom, and Christendom was the totality of European society. It was a way of life which had for its first purpose the worship of God and after that the salvation and civilization of man. Its members were the inhabitants of western Europe led and comforted by their parish priests, ruled and -- according to chance -- abused or protected by their lords and bishops, who all together glimpsed only occasionally and from afar the passing might and splendor of emperors and popes. It is this church which Professor baldwin has described with a skill and accuracy grounded in historical discipline and with a sympathy and understanding derived from religious faith.