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 nonfiction 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.

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.