The Darkness of God is a brilliant collection of studies in Western medieval theology (or, as this particular strand of thought is called today, "mysticism") on apophatic theology - that is, the theology of "unsaying" and "unknowing". A significant part of Turner's thesis is that it is entirely inaccurate to read much of medieval theology/mysticism as being "experiential" - that is, concerned primarily with subjective, ecstatic experiences of God. Rather, much of apophatic theology existed as a type of non- or anti- experientialism. It was more concerned with the exposition of certain Biblical modes of thought and theological ways of speaking of God's transcendence: all theological negation must itself be negated.
Western mysticism is suspended between two poles of early Christian thought: Augustinian interiority, in which the self understand her or himself as being made in the image of God the Trinity on the one hand and, on the other hand, the writings of Dionysius the Aeropagite (also known simply as St. Denis or Denys, now called Pseudo-Dionysius due to Renaissance, Protestant and modern suspicion concerning his real identity as being that of an unknown and unnameable 5th or 6th century Syrian monk), whose mystical writings on negative theology, inspired heavily by the Exodus narrative of Moses ascending Mt. Sinai, were just as influential. It is the dialectic of Trinitarian cataphasis ("saying") and Mosaic apophasis ("unsaying") that gives this medieval thought its dynamic.
In many ways, this dialectic reaches its summit in the writings of St. Bonaventure, "the Prince of the Mystics" and greatest known disciple of St. Francis of Assisi who wrote simply and profoundly "Christ is all our language of God". Thinkers such as Meister Eckhart are also engaged; unlike Dionysius who recieves only one essay, Eckhart - like Augustine - recieves two essays. The anonymous author of the popular and well-loved 14th century English work The Cloud of Unknowing is discussed, and after him Denys the Carthusian, a fifteenth century mystical writer and, finally, St. John of the Cross, "the Mystical Doctor" of the 16th century.
It is from Eckart to John of the Cross that Turner covers some thematic developments, concluding his study with a fine essay titled "From Mystical Theology to Mysticism". It is in the High Middle Ages that there is an increasing transformation of mystical theology from being non-experiential to being explicitly aimed against any notions of subjective experience. Insofar as Turner is discussing negative theology, he can accurately make his claim that St. John of the Cross (for example) is not interested in "hyping" subjective experiences, but one cannot read the Mystical Doctor and think that experience is absent from his writing, especially his poems! But, to simply think - and it is at risk of being implicit in this fine work - that "experience" was absent from the thought of medieval mystics is entirely erroneous.
This, then, is the one area that the book really falls short, and readers should not be under the presupposition that the medieval and high medieval era were against what Turner negatively refers to as "experientialism". The intimate experience of God was deeply important to many, including cataphatic "mystics" such as St. Bernard of Clairvaux. This book is a well written and deeply insightful look into "Negativity in Christian Mysticism" (the subtitle), but it would have been welcome if Turner had placed apophatic theology into dialogue - and dialectic - with other forms of theology/mysticism that are not *today* considered "apophatic". Perhaps it is ironic that it is those mystics considered to be "apophatic" *today* that are used by Turner to fight against the notion, equally present *today*, that apophaticism is all about individual experience. This irony should not detract, however, from the depth, rigor and intellectual and spiritual stimulation that these dense and thoughtful essays will bring to its readers.