This book was... fine, I guess. At least, I think it was anyway. It seems that the authors couldn't decide if they wanted it to be a scholarly work or a devotional one, so they settled on both and ended up with a bit of neither. That is, the authors regularly cite, rely on, and refute scholarly sources (as any good scholarly work would do); AND each chapter includes a series of devotional/reflective questions for the reader (as most popular devotionals do). The mix is... odd, to say the least.
I suppose it may be the case that this book is intended to be apologetics directed at the scholarly community, which would actually make sense given the approach the authors take. And this at least is interesting: in essence, they grant all the arguments of the higher criticism (something not really necessary, since at this point higher criticism is on its last academic legs anyway) and argue that the Trinity is still clearly discernible in the pages of Scripture. This can be a useful exercise: find the rare holdout who holds to the higher critical view of the text (at this point they're probably going to be over 50) and have them show you what books/passages of Scripture are legitimately from the hands of the Apostles. Odds are you're going to be left with much of Mark, the passages that are found in both Luke and Matthew, Galatians, James, and one or two other books. From these, even having granted absolutely everything to the person in the higher critical school, you can still defend all the traditional doctrines of the church: the Trinity, the humanity and Divinity of Christ, the substitutionary atonement, etc. The authors have basically done just that with the Trinity in this book.
The result, unfortunately, is a book that is going to be inaccessible to the layman and uninteresting to the academic. The terminology of "Q", for example, is going to be a bit heavy for someone without a background in textual arguments to sift through, while the orthodoxy of the author's position is going to drive away the average academic.
All that to say that The Shadow of the Almighty is fine theologically, but is dense and technical enough that the average joe isn't likely to want to wade through it and orthodox enough that the average academic (we need a name for that--the "average albert?") isn't going to want to.