I traced a copy of George Orwell’s “1984” to the library of the social sciences department at Warsaw University, a literary treasure trove heavy with the scent of dust and old paper, and so jammed with shelves that in places the only way to move around was sideways. For months I had been searching for this particular volume, a book that had played, in my view, a small but significant role in winning the Cold War.

There are myriad reasons the Eastern Bloc collapsed in 1989. The economic stagnation of the East and the war in Afghanistan are two of the most commonly cited. But literature also played its part, thanks to a long-running U.S. operation conducted by the Central Intelligence Agency that covertly moved millions of books through the Iron Curtain in a bid to undermine Communist Party censorship.

While it is hard to quantify the program’s effect in absolute terms, its history offers valuable lessons for today, not least since some of the very same titles and authors the C.I.A. sent East during the Cold War — including “1984”— are now deemed objectionable by a network of conservative groups across the United States.

First published in English in 1949, Orwell’s novel describes the dystopian world of Oceania, a totalitarian state where the protagonist, Winston Smith, works in a huge government department called the Ministry of Truth. The ministry is ironically named: Its role is not to safeguard the truth but to destroy it, to edit history to fit the present needs of the party and its leader, Big Brother, since, as the slogan runs, “Who controls the past controls the future: who controls the present controls the past.”

In the real Soviet system, every country had its equivalent of the Ministry of Truth, modeled on the Moscow template. In Poland, the largest Eastern European nation outside the Soviet Union, this censorship and propaganda apparatus was called the Main Office for the Control of Presentations and Public Performances, and its headquarters occupied most of a city block in downtown Warsaw.

From art to advertising, television to theater, the Main Office reached into all aspects of Polish life. It had employees in every TV and radio station, every film studio and every publishing house. Every typewriter in Poland had to be registered, access to every photocopier was restricted, and a permit was needed even to buy a ream of paper. Books that did not conform to the censor’s rules were pulped.