Alain Besançon’s studies, over  decades, on Russia, France, Islam, and art have convinced him that “that nothing is comprehensible if one neglects the religious choices that       determine a historical destiny.” His aim is to comprehend the most powerful nation on   the earth, and he was convinced that Protestantism was the key to America. The question of Protestantism and its origins implicated, in turn, the origins of the Reformation and  thus the problem of the moral and political meaning of Christianity itself. And Besançon traces theological dynamic that was to stamp the Reformation, behind Luther’s break   with Rome, to the late medieval nominalists’ failure to maintain the fragile communion that Thomas Aquinas had articulated between love and intellect.      This then is the ambition of this elegant and magisterial essay: to explore the question  of the spirit of America as bound up with the most fundamental and most problematic promise of Christianity: the union of heart and mind. This exploration leads the reader, after a deft analysis of Nominalism, through a luminous tour of the sources of modern Christianity that includes the revival of speculative mysticism in authors such as Meister Eckhart and Tauler, the devotion moderna, the main figures and movements of the Reformation proper, a brilliant digest of Anglicanism, and a survey of Puritanism in England and America. This uniquely synoptic exploration concludes with the emergence  of a democratic religion of humanity, a faith whose future is as uncertain as its grasp of   the modern spirit’s Christian sources that Alain Besançon has so judiciously laid bare.