I love this book. It also infuriates me. The biggest problem with the book is the frequent use of foreign words and phrases that are neither transliterated, translated, or defined. This makes large sections of the book unintelligible to the educated lay reader. This, in my opinion, makes the book a vanity project, one written by an academic to impress fellow academics. It is irritating to have to use an online Greek typewriter to type in συνεργεια, then copy it into Google translate to discover that it means synergy. To make sense of this book, as good as it is, means I have to do this for almost every paragraph. It is ironic that a book intending to explain Pseudo-Dionysius the Areopagite ends up being harder to read than Dionysius himself.
To be fair, this may be a problem with the editor rather than the author. If I was the editor, I would insist all foreign words be transliterated and translated. I would also insist that all foreign phrases be translated in the footnotes.