Ineffability - that which cannot be explained in words - lies at the heart of the Christian mystical tradition. It has also been part of every discussion of religious experience since the early twentieth century. Despite this centrality, ineffability is a concept that has largely been ignored by philosophers of religion. In this book, Bennett-Hunter builds on the recent work of David Cooper, who argues that the meaning of life can only be understood in terms of an ineffable source on which life depends, and engages with the work of continental philosophers, such as Heidegger, Merleau-Ponty and Karl Jaspers. This is the first book to explore the concept of ineffability within contemporary philosophy of religion and provides a starting point for further scholarly debate. It will be of interest to scholars of philosophy of religion, theology, existentialism and phenomenology.