In Medieval Christianity, visions, dreams, and apparitions were an important means of communication with the invisible realm of the divine. Conversion into material images made these exclusive and fugitive experiences accessible to a larger group of beholders. Pictorial representations of visions were among the key subjects of medieval art. Pictures of visions were not just illustrations of a sacred story, they always contributed to a discourse about the borders between the visible and the invisible, the outer and the inner eye, body and soul. Rather than imitating the visionary experience, medieval artists were interested in mapping visions as an interaction across tresholds. For the first time, this book gives an overview of pictorial representations of visions in medieval art. Three larger configurations are taken into consideration: visions as a model for the process of reading, meditating and interpreting sacred scripture, visions as perception located in an inner topology of the human soul, and visions as a miraculous activity that is verified by corporeal traces.