That book was A Place of Greater Safety, by Hilary Mantel. I bought it in the National Theater's gift shop, which I thought was a fair recommendation of its relevance to the theater's repertoire. The recommendation was well taken: as an overview of the French Revolution, the book was great. It has fabulous dialogue and sexy characters. As a novel, however, I'm not sure it holds together.
In fairness, one of the problems is the French Revolution itself. It went on for way too long. After its eruption in 1789, it wasn't decisively finished until 1799, when Napoleon asserted himself. This length of time is exorbitant excess. Revolutions, to take a page from Gilbert & Sullivan, should be a "short, sharp shock"; even before the Internet, a decade was much too long for a revolution (just ask the Chinese about the Cultural Revolution).
But another problem is that Hilary Mantel wanted to cover it all - or, at least, all the fun bits. Her book ends where Georg Büchner finished Danton's Death (that is, obviously enough, with Danton's guillotining); but, whereas Büchner begins his play in 1794, just before Danton's arrest, Mantel begins her book a good deal earlier - with Danton's (and Camille Desmoulin's; and Maximilien Robespierre's) birth(s).
The material is simply too vast. Mantel sprints through it, giving us only a sketch of everything important. In place of plot, she has historical events. In place of character development, she gives her characters superb dialogue and characteristic gestures.
To break up the grind, Mantel occasionally slips out of third-person omniscient to allow one of the characters to take the helm. Presumably for similar reasons, Mantel sometimes inserts dialogue in script format. A theater bill for a play about the French Revolution is reproduced on page 242. A variety show about the French Revolution, A Place of Safety might be; a novel, it might not be. (The New York Times book review never printed a truer sentence than when it concluded, "we are left to wonder whether more novel and less history might not better suit [Mantel's] unmistakable talent.")
Mantel would have done well to have followed Büchner's example and culled the French Revolution down to a few months worthy of her focus. A five novel series about the French Revolution, each book devoted to critical events in the years she covers (and a stand-alone novel in its own right), might have been an appropriate vehicle for her ambition. A Place of Greater Safety falls short of achieving it.
On the other hand, A Place of Greater Safety is Mantel's first novel. And when debut authors pen flawed and insanely ambitious first novels, all I can say is, "Well done."
(Image of Elliot Levey and Toby Stephens in the National Theater's production of Danton's Death from The Guardian)