HUAC, the U.S. House Un-American Activities Committee, investigated subversive acts inside the U.S. It was notorious for witch hunt investigations of communist activites in government and Hollywood. Richard Nixon became famous while in this committee, investigating Alger Hiss among others.
In 1947 the HUAC began an investigation into the Hollywood Motion Picture Industry. At first so-called "friendly" witnesses were called, men unsuspected of Communist ties, but queried about their knowledge of such activities. Among the producers interviewed was Walt Disney on 24 October, 1947. He was grilled extensively about a strike at his studio and whether the organizers were Communists (he thought that they likely were). Others were Jack Warner and Louis B. Mayer, representing the studio heads, as well as Gary Cooper and Ronald Reagan (October 23, 1947), representing actors.
During the many interviews many people were named as suspected communists. These people were brought in for interviews. Ten of them, known later as the "Hollywood Ten" refused to talk, under the 5th Amendment of the United States Constitution. Nonetheless, all were found guilty of contempt of Congress and were sentenced to between six and twelve months each in federal prison.
Those who did talk, named more names. Those names were in turn called before HUAC. If they refused to name names, they were blacklisted. Over 320 people were eventually placed on the blacklist, which stopped them from working in the entertainment industry. Some used pseudonyms in order to sell scripts. Dalton Trumbo (one of the Hollywood Ten) used the name "Robert Rich", and under that name won the Oscar for Best Screenplay for The Brave One.
See also Joseph McCarthy, who was in full stride at the same time.
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