Behind the scenes of Napoleon's threatened invasion of England, a war of wits known as The Great Terror. In 1801, as Napoleon's Grande Armee faced an army of English volunteers across the Channel, a secret war of espionage and subversion was being fought by shadowy men with little-known names. New weaponsrockets, submarines, and torpedoeswere being developed in France by the American inventor Robert Fulton. Even during the lull of the Peace of Amiens,...