For almost five decades after the Second World War, Europe was divided by the longest and most heavily guarded border on earth. The Iron Curtain, a near-impenetrable barrier of wire and wall, tank traps, minefields, watchtowers and men with dogs, stretched for 4,300 miles from the Arctic to the Black Sea. No physical combat would take place along this frontier: the risk of nuclear annihilation was too high for that. Instead, the conflict would be fought in the psychological sphere. It was a battle for hearts, minds and intellects. No one understood this more clearly than George Minden, the head of a covert intelligence operation known as the ‘CIA books programme’, which aimed to win the Cold War with literature. From its Manhattan headquarters, Minden’s global CIA ‘book club’ would infiltrate millions of banned titles into the Eastern Bloc, written by a vast and eclectic list of authors, including Hannah Arendt and Aleksandr Solzhenitsyn, George Orwell and Agatha Christie. Volumes were smuggled on trucks and aboard yachts, dropped from balloons, and hidden in the luggage of hundreds of thousands of individual travellers. Once inside Soviet bloc, each book would circulate secretly among dozens of like-minded readers, quietly turning them into dissidents. Latterly, underground print shops began to reproduce the books, too. By the late 1980s, illicit literature in Poland was so pervasive that the system of communist censorship broke down, and the Iron Curtain soon followed.