“Louis Bayard was one of the most important French spies of the Revolutionary and Napoleonic eras, who led a life of adventure, privileged access and, ultimately, treachery. Elizabeth Sparrow, whose previous book was the acclaimed Secret Service: British Agents in France 1792-1815 (1999), believes Bayard to have been ‘a double if not triple agent', but by the end of this well-researched study she provides enough evidence to convict him of being that rarest of beasts: a quadruple agent.”
Full review by Andrew Roberts of Phantom of the Guillotine, The Real Scarlet Pimpernel: Louis Bayard-Lewis Duval 1769-1844 by Elizabeth Sparrow, available online in History Today, Volume 64, Issue 1, 2014.