Short answers, pulled from the story.
Samizdat was the clandestine copying and distribution of government-suppressed literature and media in Eastern Bloc countries. Copies were typically handwritten or typed in small quantities, with recipients expected to produce additional copies. Possession could result in arrest and harsh punishment.
Radio Free Europe obtained a transmitter base at Lampertheim, West Germany, in January 1950 and completed its first broadcast aimed at Czechoslovakia on the 4th of July 1950. A 1960 study found RFE had considerably more listeners than the BBC or the Voice of America. Communist authorities used sophisticated jamming techniques in an attempt to block its signal.
Georgi Markov was a Bulgarian writer and journalist who defected to the West and worked for the BBC as a critic of Bulgarian communism. He was assassinated on Waterloo Bridge in London in 1978.
Falsifiers of History was published by the Soviet Information Bureau in February 1948, one month after the U.S. State Department released a collection of documents revealing details of the Molotov-Ribbentrop Pact. Joseph Stalin personally edited the book, rewriting entire chapters by hand. It claimed American bankers and industrialists had funded German war industries and encouraged Hitler to expand eastward, and Soviet historical accounts used that version of events until the Soviet Union's dissolution.
Stalin sealed off outside access to the Soviet Socialist Republics beginning in 1935, and for twenty-five years after his death, foreign correspondents allowed inside were restricted to within a few miles of Moscow, had their phones tapped, and were constantly followed. Albania restricted visitors to six thousand per year and segregated them from the local population. Romania's Securitate suppressed information about labour camps so effectively that very little appeared in the Western press until 1990.
Der schwarze Kanal, meaning "The Black Channel", was an East German television program that took West German broadcasts and added communist commentary. The name was a pun on the German plumber's term for a sewer. It existed because West German television signals, particularly from ARD, reached most of East Germany, with the exception of parts of Eastern Saxony around Dresden.