Frankly, I was expecting this to be far more “woo-woo” that it was, following in the footsteps of the Dan Brown fellow-travelers (like several titles that have appeared here previously). On one hand, I was relieved to find that this was not really the case, however, on the other, when the author starts doing Henry Lincoln style “sacred geometry” tracing (see the doozy copied here) of complex patterns over maps, it really does help having some mystery, conspiracy, or Big Secrets to entice the reader to play along.
In this case, Mann runs the narrative closer to a history, with side-trips into philosophy (and not in the “mystery” zone), focusing on Major Pierre Charles L'Enfant, the French associate of George Washington who had been tasked with designing the new capitol city. There is a recurring question as to whether the Masons were involved (or, I suppose, to what extent Masonic philosophy was involved, being that Washington and many of the other leading lights of the day were very visible high-ranking Masons), but it's not about that.
The book looks at various influences “in play” at the time, from myths and legends current regarding the Native American tribes that had been in the area, to the emerging mythos of the U.S., and old-form European traditions. L'Enfant was from French aristocracy, his family being artists associated with the royal house (he'd even grown up at Versailles, the design of which seemed to have a not-inconsequential effect on his plans for DC), providing him with both a solid knowledge of European artistic and architectural systems, but also a less-than-democratic attitude (he seemed to regard Washington as his “royal patron”) which eventually ran him afoul of Jefferson and other elements in the social weave of the day.
The downside of not having much of “a mystery” involved is that the book is, frankly, more boring that something that's purporting to lead up to a “big secret” (as disappointing as some of those sorts of books may end up). The author spends a substantial part of the text trying to re-create the “plan” that laid behind the eventual lay-out of Washington DC, talking about “golden section” relationships, “vesica piscis” orientations, phis, pis, and lots and lots of pentagrams (and a good part of it trying to explain why things didn't lay out “exactly” to these geometries). As I've noted before, I'd be far more impressed in one of these situations if five substantial geographic locations (buildings, monuments, squares, etc.) precisely showed up on the five points of a pentagram, but somehow it's always 3-4 points “suggesting” an alignment, but no solid proof for the entire form. Admittedly, the alignments in DC do appear to be very clearly aligned to these sorts of geometries, but the whole still suffers from “woulda coulda shoulda” assumptions of “intent”.
One thing I found somewhat surprising (and, obviously, not in a good way) was how many blatant typos found their way onto the printed page here … there were several instances where a “1790's” date was rendered a “1970's” date (!) and other places where subordinate clauses were pointlessly repeated (indicating a cut-and-paste that hadn't been cleaned up). Having been an editor and a publisher, this sort of thing makes me wonder how much attention was given this project!
SPOILER ALERT! (for those folks on LibraryThing.com who are always whining about reviews that “spoil” the read) … in the final analysis, Mann feels that L'Enfant's design was very much his own creation, based on his background in the arts and architecture of Europe, and the mathematics that are implicit in the design of the city are more “classical” than the “mystical” systems that would have likely been expressed had the plan been “Masonic” (he contrasts this with the Washington Monument, which has geometries of a far more Masonic sort).
Again The Sacred Geometry of Washington D.C. is an interesting book, and can be appreciated as a history of the efforts of a notable contributor towards the definition of the USA, but almost hampered by the whole “let's draw pentagrams on the map!” aspects. Despite my getting this on "clearance", it's still available from bn.com ... although (as is often the case for B&N published books) only available in the "aftermarket" via Amazon. If you find this sort of geometric symbology fascinating, by all means pick this up; if you're interested in post-revolutionary history, you'll likely find this reasonably engaging; but if you're looking for Deep Dark Secrets worthy of a Nicolas Cage adventure, I think you'll be disappointed in this book ... as always, YMMV, but with a cover price of $7.95 for a hardcover, you won't be out much getting it.