The iconography is astounding, very well researched, so much so that the pictures uncovered by McKenna are already spreading everywhere on the Net.
Overall, the book shows McKenna devoted himself to a painstaking and most likely time-consuming work of archival research, which resulted in an excellent harvest from him, and for us.
The reverse of the medal is that this book reads more like a novel than like a historical essay, and although McKenna is an excellent researcher, he is a poor novelist, alas. His main shortcoming is his verbosity, especially evident when he repeats in the same statement the same concept with a different set of adjectives or a different example up to four or five times.
What makes this book more of a novel than of a history book is also the fact that McKenna devotes much time and space in reconstructing intimate thoughts and emotions of the characters which mostly come from his fantasy, but sometimes are real quotations from letters and other documents, making it hard for the reader to tell what comes from the records (more often than nor summarised rather than quoted verbatim) and what comes from McKenna's imaginative power.
The book is in sum rich in new, fresh details, proposing a fascinating dearth of untapped facts and documents, but also more of a novel than of a historical source (a 40-pages paper would have sufficed to expose all of the historical discoveries contained in the 396 pages of this never-ending book: I had to skip pages and pages of intimate thoughts and hopes and fears of the characters in order to survive till the most-sought end page).
A very good reading for anybody looking for a novel, since it is based on a somewhat "queer" (in all senses) fact which caused quite a fuss in Victorian England, a somehow disappointing result for anyone, like me, who approached the book in order to get a historical assessment of the evidence available.
Still, this is currently the most accessible and most readable account of the events for anyone uninterested in a scholarly approach on the matter.