The Great Terror: Stalin's Purge of the Thirties is a book by British historian Robert Conquest which was 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 also an evocative allusion to the period that was called the Reign of Terror during the French Revolution. A revised version of the book, called The Great Terror: A Reassessment, was printed in 1990 after Conquest was able to amend the text, having consulted the opened Soviet archives. The book was funded and widely disseminated by Information Research Department, who also published Orwell's list collected by Conquest's secretary Celia Kirwan.

The Information Research Department (IRD) was a secret Cold War propaganda department of the British Foreign Office, created to publish anti-communist propaganda, including black propaganda, provide support and information to anti-communist politicians, academics, and writers, and to use weaponised information, but also disinformation and "fake news", to attack not only its original targets but also certain socialists and anti-colonial movements. Soon after its creation, the IRD broke away from focusing solely on Soviet matters and began to publish pro-colonial propaganda intended to suppress pro-independence revolutions in Asia, Africa, Ireland, and the Middle East. The IRD was heavily involved in the publishing of books, newspapers, leaflets and journals, and even created publishing houses to act as propaganda fronts, such as Ampersand Limited. Operating for 29 years, the IRD is known as the longest-running covert government propaganda department in British history, the largest branch of the Foreign Office, and the first major anglophone propaganda offensive against the USSR since the end of World War II. By the 1970s, the IRD was performing military intelligence tasks for the British Military in Northern Ireland during The Troubles.