The Parisian authorDurtalis hard at work on his biography of the French knight and notorious child-murderer Gilles de Rais, but the question of how a confidant of Joan of Arc became such a figure of depravity is difficult to answer. Turning to his friend and confidant Des Hermies, he gradually discovers that the Satanism of de Rais’ time is not only still active in the Paris of the 1890s, but...