The Great Terror: Stalin's Purge of the Thirties is a book by British historian Robert Conquest, published in 1968. It gave rise to an alternate title of the period in Soviet history known as the Great Purge. Conquest's title was in turn an allusion to the period that was called Reign of Terror (French: la Terreur, and, from June to July 1794, la Grande Terreur -the Great Terror-) during the French Revolution.