Mitch Waldrop in National Geographic:
Albert Einstein was already a world-famous physicist when the FBI started keeping a secret dossier on him in December 1932. He and his wife Elsa had just moved to the United States from their native Germany, and Einstein had been very vocal about the social issues of his time, arguing publicly against racism and nationalism.
By the time of Einstein’s death on April 18, 1955, that FBI file would be 1,427 pages long. Agency director J. Edgar Hoover was deeply suspicious of Einstein’s activism; the man was quite possibly a communist, according to Hoover, and was certainly “an extreme radical.”
Einstein himself probably would have laughed out loud at those labels if he’d known about them; he’d heard far worse from the Nazis back home. And he was not at all intimidated by officialdom. “Unthinking respect for authority is the greatest enemy of truth,” he declared in 1901.