In The Religion of the Heart, Campbell surveys European and British pietistic movements of the 17th and 18th centuries. During the period of inter-Christian warfare in the 17th century a distinctive form of religious life emerged in varied cultural contexts that stressed the encounter with the divine through the affections, especially penitence and love for God. A variety of movements - Jansenism, Quietism, Puritan and Quaker spiritualities, Reformed and Lutheran peitism, the Evangelical Revival (including early Methodism), Hasidic Judaism, and Eastern Christian devotional - advanced this form of religious life. Specific concomitant traits, such as popularity among the middle classes, leadership roles of laymen and women, intensely personal views of the deity, and the importance of personal religious experience, were shared by followers of the movements. The author suggests that these religion of the heart movements were in many respects a cultural parallel to the rise of Enlightenment thought, diverging sharply from the Enlightenment in their positive appropriation of religious tradition, but also sharing some similarities, such as their concern with experience as a source of knowledge. Campbell is one of the few scholars to study these movements as a widespread European cultural phenomenon. In doing so, he offers a critical but sympathetic examination of the movements considering their expressions of a form of religious life characterized by personal affection for God and showing why they are important to our understanding of modern religious movements.