There's a lot wrong with this book as a work of history.
Cerami speculates a lot, especially in the first half, about the thoughts and feelings of his subjects--speculation based upon his impressions of them which he has gleaned from other biographies.
The endnotes are a complete disaster--I jumped back many times to find sources, and was often left hanging. The bibliography consists almost entirely of biographies of the main historical giants, and a general reference to "Letters", and very few primary sources. Its perspective is too skewed--Napoleon is a shadowy colossus across the sea, Talleyrand a diplomatic genius whose flaws (Cerami suggests) we must overlook to appreciate his character, while Jefferson and Madison are the dynamic duo. Jefferson actually comes off a little strange, threatening war until du Pont suggests the purchase. This skew goes so far, at one point, as to refer to America's budding State Department as "our".
It is a very readable account of an important event, but the breezy style goes too far, e.g. referring to the "Jefferson-Madison Theatrical Society".
This book or one like it would be an interesting read prior to a bio of Aaron Burr. At one point Madison tries to convince Pichon that France should not provoke the US to expand into the territory--"It would surely give birth to a second American state, certain to clash with the Eastern part..." (No endnote.) ( )