What is the HUAC and what did it set out to do in the 1940s and 1950s and what does it have to do with The Crucible?

The House Unamerican Activities Committee (HUAC) was a congressional group designed to "root out" individuals who were Communists or suspected of being Communist in post World War II America.  Led by Senator Joseph McCarthy of Wisconsin, HUAC was a vehicle to enhance the "Red Scare" of the 1950's.  This particular brand of paranoia was built on the premise that Communists were rapidly infiltrating all aspects of American society.  McCarthy developed a "list" of individuals whom he suspected to be Communists.  The growing distrust of the Soviet Union, as well as the general fear of Communism, allowed him to assume a greater stage, as few raised their voices in opposition and were equally driven by the fear of Communists.  McCarthy and his committee would call individuals to testify about their beliefs as well as the beliefs of others in their allegiance to the United States and against Communism.  Few raised their voice in opposition and those who did were immediately branded as "Communists" or "sympathizers" with Communism.  As McCarthy used the media as his tool to elevate his own status, the climate of fear and paranoia supplanted American visions of justice and fairness, including the presumption of innocence.

Miller, himself, was called in front of this committee and refused to answer any of its questions.  In a moment of courage, Arthur Miller proved himself to be more of a patriot than anyone else could envision as he refused to allow the American notions of institutional equality be vitiated by a climate of fear and manipulated by people like McCarthy.  His work, The Crucible, is an application of these ideas set against the backdrop of the Salem Witchcraft Trials.