FOR A MAN often vilified as one of the greatest monsters in European history, Maximilien Robespierre lived the first five-sixths of his life in remarkably conventional fashion. As an earnest, prizewinning scholarship boy, and then an ambitious young provincial lawyer in late eighteenth-century France, he gave few hints that he would soon become the major figure in a revolutionary Reign of Terror. His early life did have its share of destabilizing tragedies: the death of his mother when he was six, followed by his father’s effective abandonment of the family. But whatever demons these events engendered manifested themselves mostly in a ferocious work ethic, personal rigidity, and quite possibly a severe case of sexual repression. By the time he was thirty, in 1788,...