Slander has always been a nasty business, Robert Darnton notes, but that is no reason to consider it a topic unworthy of inquiry. By destroying reputations, it has often helped to delegitimize regimes and bring down governments. Nowhere has this been more the case than in eighteenth-century France, when a ragtag group of literary libelers flooded the market with works that purported to expose the wicked behavior of the great. Salacious or seditious,...