How and why theological discourse uses religious experience? What kind of reflection was there about religious experience in the past? At what point during the history of Christianity did religious experience become an important epistemological category? What paradigm changes were at the basis of the diverse interpretations of religious experience? These are some of the questions addressed in this volume, a theological history of ideas, about the historical development of the meaning of religious experience and how it evolves from a mode of knowing to an object for knowledge. In general, during Antiquity and the Middle Ages, theology creates experience, and in certain modern and post-modern currents, experience creates theology: an end becomes a means. With regard to Antiquity, the Middle Ages, and Modernity, the author examines what is meant by religious experience and drafts the evolution of an intellectualistic concept that changes into an emotionally charged concept. Two research questions however recur: what do the different writers, during different periods, mean by religious experience, and what is the object of that experience?