For his holiday reading in the summer of 1835, the literary and political journalist John Wilson Croker packed the printed lists of those condemned to death during the Reign of Terror in revolutionary France. The several thousand guillotined in Paris after the establishment of the Revolutionary Tribunal (10 March 1793) and before the fall of Maximilien Robespierre (27 July 1794), were accused of crimes ranging from hoarding provisions or conspiring against the republic to sawing down a tree of liberty or declaring ‘A fig for the nation!’ In horrified disbelief Croker asked the question that has never gone away: how...