Interesting premise and subject, a little bit of a dry delivery. Bibliography/references appear very well researched and documented. The only assertions I found (after an admittedly not too assiduous quest) to be a bit questionable are at the end (pp. 250, 260, 261).
Clearly, Mr. Grey feels passionately about this subject. His book is a mix of seemingly factual stories, which regularly include varying degrees of artistic license in order to illustrate his points and, presumably, to entice interest.
Due to incessantly looking up pretty every one of his many numbered sources/references, found myself wishing they were footnoted (instead of listed by chapter at the back of the book). But that fact does not color my opinion of the book.
From it, I learned a lot, and that's a good thing.