If It's "Inexpressible" How Did You Manage to Write a Book about It?

I've previously mentioned a number of recent books looking at Ps-Dionysius. Two more join that pile, both taking a more "philosophical" approach at least as that term is defined by the (post-?) modern academy. First is Melanie Walton, Expressing the Inexpressible in Lyotard and Pseudo-Dionysius: Bearing Witness as Spiritual Exercise (Lexington Books, 2013), 326pp.

About this book the publisher tells us:

The event happens. To it, you bear witness; to it, you are commanded to testify; and yet, by the command and by the event, you are unable to speak. Testimony demands the witness to demonstrate her knowledge—that knowledge that she must have by the fact of being a witness to something. And, yet, this something exceeds the possibility of its grasp by any manner that could yield its expression amenable to verification. One example is the Holocaust survivor silenced by the odious logic of the historical revisionist who forbids the living to evidence death camps. The horror of the example is not just the difficulty of actually undoing such a foul bind that masks hatred with sophistic flourish; it is the realization that the bind’s power is fueled by the true inexpressibility of the Holocaust itself. A second example is the religious faithful called to testify to that superessentiality who supremely exceeds every capacity to know Him. While heterogeneous in time, place, and philosophical situation, the contemporary French father of postmodernism, Jean-François Lyotard, and the late antique, presumably Syrian father of Neoplatonist Christian mysticism, Pseudo-Dionysius, both do justice to their witnesses by endeavoring under this weight of impossibility to express the inexpressible. Lyotard rigorously analyzes every aspect of the differend and explores a plethora of attempts to lift the silence, and finds each to fail. Pseudo-Dionysius founds a radical, stuttering method of speaking and unspeaking the names of God to give forth this inconceivable testimony. Expressing the Inexpressible undertakes a critical reading of each individually and then brings their distinct methods to bear on their shared problem of that which resists its articulation. Their conjunction finds its voice in a reading of silence and eros as forging a new idiom by which the witness may do the impossible: express the inexpressible. 

The second, shorter book was published a little earlier: Michael Craig Rhodes, Mystery in Philosophy: An Invocation of Pseudo-Dionysius (Lexington, 2012), 142pp.

About this book we are told:

Typically, mystery does not receive much attention in philosophy. Although Heidegger and other key philosophers have made a place for mystery in philosophy, many find such philosophizing suspect and unconvincing. As a general rule, contemporary philosophers have taken a different approach, and, thus, there has been very little discussion of mystery in philosophy. As a study of mystery in philosophy, this book is therefore somewhat unique. Moreover, it is also distinctive in the way it approaches the subject, tuning to an unpopular figure—Dionysius the Areopagite (c. 500)—in contemporary philosophy in effort to make connections between that form of thought and various claims and indications of mystery. Thus, the book is unconventional in terms of both its subject matter and its methodology.