The work of Timothy Tackett on the French Revolution has made him one of its most influential recent historians. As long ago as 1986 he produced a still-definitive analysis of the first and deepest divide within the Revolution, the split among Catholics over the clerical oath of 1791. Ten years later he traced in unprecedented and entirely convincing detail the process by which the men who made the Revolution of 1789 were radicalised. In 2003 he offered a refreshing discussion of the impact of another great turning point, the king’s flight to Varennes in 1791. All three of these books enjoyed the rare distinction of being translated into French, and no general history of the Revolution could be written today without making use of their findings. Now he turns his attention to the classic issue which has dogged the reputation of the French Revolution ever since it happened: how the reforming promise of 1789 turned, over a few short years, into the bloodbath of the Terror.