This dissertation will make a contribution to debates on mysticism and religious experiences by exploring the neuroscientific and medical studies performed on the Medjugorje visionaries and analyze what hermeneutical contributions these studies make to our understanding of extraordinary religious experiences. In June 1981, in the village of Medjugorje, Bosnia-Herzegovina (the former Yugoslavia), five teenagers and one child reported experiencing daily apparitions of the Virgin Mary, visionary experiences. Three of the six visionaries report to continue experiencing daily apparitions as adults. Throughout the past three decades, the Medjugorje visionaries have been subjected to an extensive amount of medical, psychological, and scientific examination, even while experiencing their apparitions. An exploration of the various scientific studies related to the visionaries of Medjugorje adds to our understanding of extraordinary religious experiences and responds to the need for incorporating new, multidisciplinary approaches to the study and interpretation of religious and mystical experiences. This dissertation examines the major hermeneutical and epistemological debates surrounding the topic of religious and mystical experiences, tracing the major philosophical developments of the twentieth century. Using a constructive-relational method, this study presents and analyzes the scientific examinations on the Medjugorje visionaries in juxtaposition, for the first time, with the major scholars and hermeneutical discourses focusing on religious experience. This dissertation demonstrates that the scientific studies on the Medjugorje seers make a threefold contribution: a contribution that is epistemological, hermeneutical, and that strengthens a criteria of adequacy in discerning religious experiences. The scientific studies in Medjugorje challenge an epistemological reductionism that denigrates every extraordinary religious phenomenon, such as visionary experiences, into a pathological or natural category of interpretation. Making a contribution to the history of hermeneutical debates about mystical experiences, the scientific studies on the Medjugorje visionaries point to something more in the experiences that the visionaries undergo through empirical examination of their apparitional phenomena.