MOSCOW—Alexander Solzhenitsyn, the Nobel Prize-winning Russian author whose books chronicled the horrors of dictator Josef Stalin’s slave labor camps, has died of heart failure, his son said Monday. He was 89.

Stepan Solzhenitsyn told The Associated Press his father died late Sunday in Moscow, but declined further comment.

Through unflinching accounts of the eight years he spent in the Soviet Gulag, Solzhenitsyn’s novels and non-fiction works exposed the secret history of the vast prison system that enslaved millions. The accounts riveted his countrymen and earned him years of bitter exile, but international renown.

And they inspired millions, perhaps, with the knowledge that one person’s courage and integrity could, in the end, defeat the totalitarian machinery of an empire.

Beginning with the 1962 short novel “One Day in the Life of Ivan Denisovich,” Solzhenitsyn devoted himself to describing what he called the human “meat grinder” that had caught him along with millions of other Soviet citizens: capricious arrests, often for trifling and seemingly absurd reasons, followed by sentences to slave labor camps where cold, starvation and punishing work crushed inmates physically and spiritually.

His “Gulag Archipelago” trilogy of the 1970s shocked readers by describing the savagery of the Soviet state under the dictator Josef Stalin. It helped erase lingering sympathy for the Soviet Union among many leftist intellectuals, especially in Europe.

But his account of that secret system of prison camps was also inspiring in its description of how one person — Solzhenitsyn himself — survived, physically and spiritually, in a penal system of soul-crushing hardship and injustice.

The West offered him shelter and accolades. But Solzhenitsyn’s refusal to bend despite enormous pressure, perhaps, also gave him the courage to criticize Western culture for what he considered its weakness and decadence.

After a triumphant return from exile in the U.S. in 1994 that included a 56-day train trip across Russia to become reacquainted with his native land, Solzhenitsyn later expressed annoyance and disappointment that most Russians hadn’t read his books.

During the 1990s, his stalwart nationalist views, his devout Orthodoxy, his disdain for capitalism and disgust with the tycoons who bought Russian industries and resources cheaply following the Soviet collapse, were unfashionable. He faded from public view.

But under Vladimir Putin’s 2000-2008 presidency, Solzhenitsyn’s vision of Russia as a bastion of Orthodox Christianity, as a place with a unique culture and destiny, gained renewed prominence.

Putin now argues, as Solzhenitsyn did in a speech at Harvard University in 1978, that Russia has a separate civilization from the West, one that can’t be reconciled either to Communism or western-style liberal democracy, but requires a system adapted to its history and traditions.

“Any ancient deeply rooted autonomous culture, especially if it is spread on a wide part of the earth’s surface, constitutes an autonomous world, full of riddles and surprises to Western thinking,” Solzhenitsyn said in the Harvard speech. “For one thousand years Russia has belonged to such a category.”

Born Dec. 11, 1918, in Kislovodsk, Solzhenitsyn served as a front-line artillery captain in World War II, where, in the closing weeks of the war, he was arrested for writing what he called “certain disrespectful remarks” about Stalin in a letter to a friend, referring to him as “the man with the mustache.”

He served seven years in a labor camp in the barren steppe of Kazakhstan and three more years in internal exile in Central Asia.

That’s where he began to write, memorizing much of his work so it wouldn’t be lost if it were seized.

His theme was the suffering and injustice of life in Stalin’s gulag — a Soviet abbreviation for the slave labor camp system, which Solzhenitsyn made part of the lexicon.

He continued writing while working as a mathematics teacher in the provincial Russian city of Ryazan.

The first fruit of this labor was “One Day in the Life of Ivan Denisovich,” the story of a carpenter struggling to survive in a Soviet labor camp, where he had been sent, like Solzhenitsyn, after service in the war.

The book was published in 1962 by order of Soviet leader Nikita Khrushchev, who was eager to discredit the abuses of Stalin, his predecessor, and created a sensation.