All the other reviews describe the book well. But no one mentioned the biographical sketches of such historical figures as Catherine the Great, Napoleon, Bach, Marat, Rousseau, Talleyrand, Benedict Arnold, etc. that are an integral part of the novel.
Of course the stories of these persons are fictionalized in the book, but the ability of Ms. Neville to weave such realistic portraits of legends into the epic story she tells is fascinating and adds greatly to the appeal of this book.
Also, let's not forget the education she gives us in chess, math, computers, the French revolution, alchemy, Mediterranean mythology, Algiers, OPEC, puzzles, Fibonacci numbers and freemasonry.
Oh, and before anyone thinks that a book that covers the above topics must be pedantic, boring and complicated, let me state emphatically that this book is FUN. It's a hoot. It's engaging. It's engrossing.
Finally, my copy of this book is starting to fall apart from overuse. It's time to get a new copy.
And Ms. Neville, if you're reading this, please write another book. I can't wait.