The idea of progress, the doctrine that involves the belief that every day in every way the world grows better and better, has dominated the civilization of Western Europe in modern times. Far more than merely a philosophical opinion or the doctrine of a school, it has permeated the whole mind of society. This book analyzes the theory of progress in a panoramic study which examines the interrelation between religion and culture of all the major civilizations of the world. The author maintains that the vital, creative power behind every culture is a spiritual one. All civilizations have a common element, religion, "the key to history", which influences every human activity; and he specifically demonstrates that Christianity is the religion that gave Western culture its being. The rise of the theory of progress has led to the secularization of modern civilization and the decline of spiritual influence.