Recent years have seen growing popular absorption with ‘spirituality’ in all its forms. But as this study shows, it is largely separated from theology. Spirituality has grown more self-referential and is subverted by consumerist mentality, while theology has grown critically proficient but uneasy in speaking from or to the heart of Christian mysteries. Through a study of exemplary writers such as Gregory of Nyssa, McIntosh recovers an understanding of the inner integrity of mystical consciousness and theological expression. The final chapters test the possibility of renewed conversation between spirituality and theology by drawing on spiritual traditions to re-think contemporary problems in Trinitarian thought, christology, and the understanding of the self. This book offers not only an analysis of spirituality and theology in the eras of their united activity, but also a hermeneutic for the theological appropriation of spirituality and a sustained argument for the renewal of mystical theology.