Although it has long been acknowledged that early Irish literature contains both pre-Christian and Christian elements, there’s been no sustained study of the challenges involved in understanding the interrelation of these worldviews. draws attention to the importance of reconsidering the relationship between religion and mythology, as well as the concept of “Celtic religion” itself. When scholars are attempting to construct the Celtic belief system, what counts as religion, and how does that differ from mythology? This volume, the first interdisciplinary collection of articles to critically re-evaluate the methodological challenges of the study of Celtic religion, will appeal to both scholars and lay readers of Celtic literature, as well as anyone interested in ancient and medieval cultures.