This book explores the philosophical development of some theological metaphors central to the mystical traditions of the medieval Christian West. These metaphors play a crucial role in defining the negative or apophatic style of mysticism, best known in the author of The Cloud of Unknowing. Turner traces the history of these metaphors from Augustine to John of the Cross, through Denys the Areopagite, Hugh of St Victor, Thomas Gallus, Bonaventure, Meister Eckhart, the Cloud author and Denys the Carthusian. He concludes that whereas the classical medieval tradition maintained a close connection between the metaphors and the negative dialectics of neo-Platonism, the contemporary reading of that tradition retrieves the metaphors but severs their relationship with the dialectics. The result is that we read the medieval tradition as promoting a mysticism of negative experience, whereas that tradition in fact contained a powerful critique of experientialism.