This chapter argues that secularization is proceeding apace on both sides of the Atlantic — at different speeds and at different levels. It describes systematic and consistent evidence establishing the variations in religiosity among postindustrial nations, in particular, contrasts between America and Western Europe. It compares and contrasts two alternative explanations for transatlantic differences: the religious market theory postulates a link between levels of religious competition and levels of religious observance; the secure secularization theory is the view that levels of societal modernization, human development, and economic inequality drive levels of religious belief and activity.
Keywords: religiosity, postindustrial nations, United States, Western Europe, religious market theory, secure secularization, economic inequality