The Gulag was the Soviet Union's system of forced-labor camps, run by the secret police, through which millions of prisoners passed between roughly 1930 and the mid-1950s. Its name is an acronym for the government office that managed the camps, and it came to stand for the whole world of Soviet forced labor: the camps, the sentences, and the literature of survival written by those who lived through them. The system reached its height under Joseph Stalin and was dismantled in the years after his death in 1953.
Spread across the emptiest reaches of the largest country on earth, the camps formed a kind of nation that appeared on no map. Its citizens were the condemned, its borders were the Arctic cold and a thousand miles of forest, and its geography was known in full only to those sentenced to cross it. When a former prisoner finally charted that hidden country in a single vast book, he had to draw it from memory and the memories of others, because the state that built it had never admitted it existed. And even now, decades after the last camp closed, the most basic question about it, how many it killed, has no settled answer.