Which 1973 nonfiction work by Aleksandr Solzhenitsyn was banned in the Soviet Union?

The 1973 nonfiction work by Aleksandr Solzhenitsyn banned in the Soviet Union was The Gulag Archipelago.

Its full title, The Gulag Archipelago: An Experiment in Literary Investigation, describes the Soviet forced-labor and prison-camp system as a vast chain of “islands” spread across the country. Solzhenitsyn assembled the three-volume work from his own experience as a prisoner, interviews, letters, diaries, legal records, and testimony from former inmates.

The first Russian edition appeared in Paris through YMCA-Press in late 1973 because publication inside the Soviet Union was impossible. The KGB had confiscated manuscripts, and the arrest and interrogation of one of Solzhenitsyn’s typists convinced him that the remaining text had to be released abroad. Soviet authorities condemned the book as anti-Soviet, and possession or distribution could bring severe punishment.

Readers sometimes confuse it with One Day in the Life of Ivan Denisovich, an earlier fictional novella that had been officially published during Khrushchev’s thaw. The Gulag Archipelago was a much broader nonfiction indictment. It circulated clandestinely in the USSR until official publication began in 1989.