Overall, this was a somewhat irritating book, by turns exciting and annoying. The exciting parts were when Ethan and the Science Boys were clicking on all cylinders, facing certain death but finding ways out at the last minute and reminding us that courage is the more praiseworthy coming from those smart enough to know exactly how hopeless their cause is but soldier on regardless than from the idiots who honestly think they are winning. The annoying parts were when the Savants were turning their great minds to the unbecoming task of finding new ways to blame everything bad that happened on Ethan Gage. (Not entirely unjustified I'll grant, but whining however wittily done is still whining and quickly grows tiresome, especially when Ethan joins in by whining about the injustice of it all to the reader!)
This is the fourth book in the series, following the as yet unread by me Napoleon's Pyramids, The Rosetta Key, and The Dakota Cipher. I wouldn't recommend jumping into the middle of the series this way, but I found plenty of back references to get me up to speed on events.
The action begins with the disastrous decision on the part of our three scientific geniuses: English geologist William Smith, French zoologist Georges Cuvier, and American inventor Robert Fulton to insist that Ethan Gage take them out drinking and whoring one night in Paris, which results in an encounter with the series villain secret nut group the "Egyptian Rite", the burning down of a brothel, the theft of a fire wagon, and their arrest by Napoleon's secret police who makes them an offer they cannot refuse: sail to the forgotten backwater island of Thira in search of evidence about the Burning Mirror of Archimedes, a weapon legend has the great mathematician using to defend Syracuse from Roman attack, and which could if real and if rediscovered, still prove useful in an age of wooden sail powered warships.
Oh, and watch out for the Barbary Pirates who have just recently declared war on the United States.
The result is mostly a wild romp through the Mediterranean as Ethan tries but often fails to keep one jump ahead of his numerous enemies and "allies" of varying degrees of reliability while protecting the "modern" world of 1802 from a potentially history changing weapon without sacrificing his country, his friends, his family, or his life, if that is even possible.
Defects? More than a few. In addition to the annoyances noted above a full third of the book: Part 2, Chapters 18 to 32, absolutely wallows in the degradation of our heroes as slaves of the Barbary Pirates. This is carried on to such an extent of unpleasantness and in such detail that I had difficulty continuing to read it. I kept putting the book down in queasiness and being reluctant to pick it up again. I suppose the author's intent was to justify Ethan's later apparent betrayal, but since that rather obviously was not the reason Ethan did what he did, it struck me as somewhat nauseatingly overdone. Another objection is to the author having by the very title implied that his novel was set during some of the most momentous events in US history but in fact setting his novel during a period in the First Barbary War when ABSOLUTELY NOTHING HAPPENED. (For that matter nothing happens in the Napoleonic Wars or the struggle for Greek independence, either.)
However, my chief objection is to what I perceive to be a rigid, self defeating series formula that keeps sending our hero off in search of some powerful long lost potentially history altering MacGuffin that Ethan must first find... and then lose past all finding by the end of the book while at the same time preventing history from changing by a single jot or tittle. In a standalone novel this could annoy; in a series it will be all but impossible to avoid tiresome repetition IMHO. I am obligated to read and review the next two Ethan Gage adventures: The Emerald Storm and The Barbed Crown, but it is an open question whether I shall ever want to read another given the utterly predictable formula on display.