A new investigation, based on previously unseen KGB documents, reveals the startling truth behind Stalin's last great conspiracy.

On January 13, 1953, a stunned world learned that a vast conspiracy had been unmasked among Jewish doctors in the USSR to murder Kremlin leaders. Mass arrests quickly followed. The Doctors' Plot, as this alleged scheme came to be called, was Stalin's last crime.

In the fifty years since Stalin's death many myths have grown up about the Doctors' Plot. Did Stalin himself invent the conspiracy against the Jewish doctors or was it engineered by...